Adoptive immunotherapy with interleukin-2 (IL-2) results in diminished IL-2 production by stimulated peripheral blood lymphocytes

We examined the responses of peripheral blood lymphocytes (PBL) to a panel of T-cell mitogens in patients receiving adoptive transfers of tumor-infiltrating lymphocytes and continuous infusions of interleukin-2 (IL-2) for treatment of advanced cancer. All patients showed diminished proliferative responses to soluble and alloantigens, lectins, anti-CD3, and IL-2 during therapy. The non-major histocompatibility complex (MHC)-restricted cytolytic activities of PBL were increased by treatment and were further augmented by IL-2in vitro. The expression of 55-kd low-affinity IL-2 receptors (IL-2R) by PBL increased during treatment but functional IL-2R were simultaneously down-regulated. Proliferative responses were partially restored to pretreatment levels when PBL were costimulated with recombinant IL-2 and mitogens. Lectin stimulation of PBL produced little IL-2 secretion during treatment, while IFN-gamma secretion persisted. We conclude that infusions of IL-2 down-regulate the expression of functional IL-2R, decrease the secretion of IL-2, and lead to decreased mitogen responses by PBL.     

Effects of IL-2 therapy in asymptomatic HIV-infected individuals on proliferative responses to mitogens,recall antigens and HIV-related antigens

The effects of IL-2 therapy on lymphoproliferative responses to mitogens, recall antigens and HIV epitopes were studied in asymptomatic HIV-infected patients enrolled in a phase II study of intermittent continuous intravenous (CIV) IL-2 and subcutaneous infusions of polyethylene glycol-modified (PEG) IL-2. Sixteen consecutive patients randomized to receive CIV IL-2 (n = 5), PEG IL-2 (n = 7) or anti-viral therapy alone (n = 4) were studied. All patients were vaccinated with tetanus toxoid (TT) before receiving therapy. Proliferative responses to phytohaemagglutinin (PHA), soluble anti-CD3, TT, streptokinase/streptodornase (SK/SD) and 11 previously described HIV-specific T-helper epitopes from gag and env were studied at weeks 0, 16, 30 and 48. Median CD4⁺ lymphocyte increases of 272 and 255 CD4⁺ cells/μl were observed in the CIV IL-2 and PEG IL-2 groups at week 48, while decreasing by 104 cells/μl in the anti-retroviral therapy alone group. At each time point proliferative responses to PHA, anti-CD3, TT and SK/SD were not different between treatment arms. Similarly, no differences in responses to HIV epitopes were found between the groups and no new responses to HIV epitopes were detected. IL-2 therapy results in a significant increase in peripheral blood CD4⁺ lymphocyte count, but this increase is not associated with quantifiable improvements in lymphoproliferative responses to mitogens, recall or HIV antigens.     

Successful bone marrow transplantation with split lymphoid chimerism in DiGeorge syndrome

A female infant with DiGeorge syndrome associated with severe T-cell immunodeficiency underwent a successful bone marrow transplantation from her HLA-identical, mixed leukocyte culture-nonreactive brother at 5 months of age. Mature circulating T cells and mitogen-induced proliferative responses were detectable at 10 days posttransplant, and by 8 months posttransplant functional T- and B-cell reconstitution was documented by normal responses to mitogens and normal levels of serum immunoglobulins as well asin vitro andin vivo T-cell reactivity to specific antigens and production of specific antibody to T cell-dependent antigensin vivo. Phytohemagglutinin-induced interleukin-2 production and cell surface interleukin-2 receptor expression improved posttransplant, with normal production values observed by 8 months posttransplant. Histologic examination of appendix and thoracic lymph node obtained 9 and 17 months posttransplant, respectively, revealed near-normal lymphoid architecture, with germinal center formation providing morphologic confirmation of reconstitution. Stable split lymphoid chimerism with T cells of donor origin and B cells remaining recipient in origin was documented by sex chromosome analysis. Two years posttransplant the subject remains free of serious infections. In conclusion, this case indicates that bone marrow transplantation can produce peripheral immunoreconstitution without need for significant thymic influence, most likely by providing a source of postthymic T cells, and that bone marrow transplantation should be considered a therapeutic option in patients with DiGeorge syndrome associated with severe T-cell deficiency.     

Mycobacterium avium Infection and Immune Restoration Disease After Highly Active Antiretroviral Therapy in a Patient with HIV and Normal CD4+ Counts

A patient infected with HIV who had normal CD4+ T-cell counts developed Mycobacterium avium complex lymphadenitis associated with restoration of delayed-type hypersensitivity responses to mycobacterial antigens after commencing highly active antiretroviral therapy (Mycobacterium avium immune restoration disease). This case provides further evidence that delayed-type hypersensitivity responses and CD4+ T-cell counts are independent indicators of the cellular immune defects induced by HIV infection and that Mycobacterium avium immune restoration disease may occur in patients with persistently normal CD4+ T-cell counts. Electronic Publication     

Altered immunity in hemophilia correlates with the presence of antibody to human T-cell lymphotropic virus type III (HTLV-III)

Twenty-nine heterosexual patients with hemophilia were investigated with histories, physical examinations, laboratory evaluations of immune function, delayed hypersensitivity skin tests, and assays for antibody to human T-cell lymphotropic virus type III (HTLV-III). Sixteen patients were HTLV-III antibody positive and 13 were HTLV-III antibody negative. No patient had the acquired immune deficiency syndrome (AIDS). Patients who had antibody to HTLV-III had received significantly more units and lots of factor concentrates in the preceding 5 years than those who did not have antibody. HTLV-III antibody-positive patients had significantly fewer total T cells (Leu-1 positive) and significantly fewer helper T cells (Leu-3 positive) than HTLV-III negative patients. Antibody-positive patients also had increased amounts of IgG and decreased thymidine incorporation in response to concanavalin Ain vitro. There were no differences inin vitro lymphocyte responses to phytohemagglutinin (PHA), pokeweed mitogen,Candida, tetanus, or purified protein derivative (PPD), no significant impairments of gamma interferon or interleukin-2 (IL-2) production, and no anergy. Ten patients with antibody to HTLV-III had immunologic studies repeated 1 year after the original evaluation. A significant increase was seen in suppressor (Leu-2-positive) T cells but not in total T-cell or helper T-cell numbers, helper/suppressor ratios, or T-cell functional assays. We conclude that the immune abnormalities in hemophiliacs are the result of contact with HTLV-III but that these abnormalities may remain stable over prolonged periods.     

Correlation of clinical parameters and immunological function with human immunodeficiency virus plasma viremia in children.

Studies of immune function in human immunodeficiency virus (HIV)-infected children are important, because functional abnormalities can precede CD4+ T-cell loss and are associated with the development of opportunistic and bacterial infections. We sought to correlate clinical parameters and immunological function with HIV RNA plasma levels in 20 children. HIV RNA levels were measured by a polymerase chain reaction assay. We analyzed T-cell responses to mitogens (phytohemagglutinin, concanavalin A, and pokeweed [PWM]) and antigens (tetanus toxoid and Candida albicans); T-cell suppressor activity; and humoral immunity to Haemophilus influenzae, hepatitis B, tetanus, and diphtheria vaccines. The median age of the children was 6 years. Eight children had HIV RNA levels less than 200 to 9621 copies per milliliter (group I). Four children had 37,970 to 82,630 copies per milliliter (group II). Eight children had 102,100 to 191,200 copies per milliliter (group III). There were no differences in the HIV-related complications between group I and II children. Group I/II children had significantly higher CD4+ T-cell counts (P = 0.02), less symptomatic HIV disease (P = 0.005), and more detectable protective vaccine immunity (P = 0.014) compared with group III children. Responses to mitogens were conserved in most children. Group I children tended to have higher responses to tetanus toxoid than group II children and significantly higher responses than group III children (P = 0.01). Group I had significantly higher responses to C. albicans than groups II (P = 0.016) and III (P = 0.001). Group I/II children tended to have lower suppressor activity compared with group III children (median, 0 vs 64%). We demonstrated that humoral and cellular immune dysfunction exists at all stages of disease in HIV-infected children but was most severe in children with greater than or equal to 100,000 HIV RNA copies per milliliter. Function was the most intact in children with less than 10,000 copies per milliliter.     

Primary cell-mediated immune response in bronchial asthma. Relationship between primary in vitro and in vivo cell-mediated and antibody responses in patients with asthma and healthy controls

Eleven patients with asthma and ten sex and age matched healthy controls were immunized with the primary immunogen Helix pomatia Haemocyanin (HPH). The amplitude and the kinetics of in vitro cell-mediated immune response were measured by HPH-induced lymphocyte proliferation. Lymphocytes were also challenged in vitro with mitogens and recall antigens. In vivo cell-mediated immunity was determined by inducing delayed type hypersensitivity reactions with HPH. Anti-HPH antibody responses in the IgE, IgG and IgM classes were measured to gain an insight into the relation between cell-mediated and humoral immune responses in patients with asthma and healthy controls. The in vitro and in vivo cell-mediated response and the IgM antibody response did not differ between patients with asthma and controls. The IgE and IgG antibody responses, however, were increased in the patients. IgM antibody response correlated with both the in vitro and in vivo cell-mediated response (R= 0.45, P<0.05). IgE and IgG antibody responses however were not correlated with cell-mediated responses. These data suggest that the primary abnormality in immune regulation in patients with asthma concerns the control of the IgE and IgG class antibody responses.     

A synthetic analogue of phosphatidylinositol mannoside is an efficient adjuvant

We recently described the synthesis of an ether linked analogue of phosphatidylinositol dimannoside (PIM₂ME). In the current study, PIM₂ME was found to significantly enhance the release of the key Th1 cytokine interleukin-12 (IL-12) by dendritic cells (DCs) of naïve mice in vitro, but not interleukin-10 (IL-10). Based on this result, it was hypothesized that PIM₂ME would be an effective adjuvant for cell-mediated immune responses. Injections of PIM₂ME alone did not lead to weight loss and did not have toxic side effects, based on biomarkers of toxicity in serum,demonstrating that the compound induced no apparent adverse side effects. Mice were vaccinated with the core antigens of the hepatitis C virus by itself or with three different adjuvants, namely PIM₂ME, a commercial preparation of monophosphoryl lipid A (MPL) or a preparation of aluminium hydroxide gel (alum). A control group of animals received the antigen only with no adjuvants. Immune responses to the Hepatitis C viral antigens were monitored by measuring antigen-specific production of interferon-gamma (IFN-γ), the p40 subunit of interleukin-12 (IL-12) and interleukin-10 (IL-10) to assess cell-mediated immune responses. Vaccination of mice with Hepatitis C viral antigens with the adjuvant PIM₂ME led to a significant increase in cell-mediated immune responses (IFN-γ and IL-12). Injection of Hepatitis C viral antigens in alum led to no enhancement of the cell-mediated immune response. We conclude that PIM₂ME is an efficacious adjuvant for enhancing cell-mediated immunity, and induces no observable adverse effects.     

Daily low-dose subcutaneous interleukin-2 added to single- or dual-nucleoside therapy in HIV infection does not protect against CD4+ T-cell decline or improve other indices of immune function: results of a randomized controlled clinical trial (ACTG 248)

CONTEXT: Approaches to preserve or enhance immune function in HIV-1 infection are needed. OBJECTIVES: To examine the ability of daily low-dose interleukin-2 (IL-2) in combination with antiretroviral therapy to preserve circulating CD4+ T-cell counts, the clinical safety and tolerability of this treatment, and safety with respect to changes in plasma HIV-1 RNA levels. DESIGN: Twenty-four-week, phase 2, multicenter, randomized, open-label trial conducted at 12 AIDS Clinical Trials Units between September 1995 and May 1997. PARTICIPANTS: A total of 115 HIV-infected persons with screening CD4+ T-cell counts between 300 and 700 cells/mm who were on stable single- or dual-nucleoside therapy for at least 2 months, 11% of whom were also on a protease inhibitor at study entry. INTERVENTIONS: Patients were randomly assigned to receive IL-2 at a dose of 1 million IU subcutaneously once daily plus continued anti-retroviral therapy (ART + IL-2, n = 57) vs. continued ART alone (ART alone, n = 58). IL-2 dose reductions were made for objective or subjective toxicities. All subjects randomly assigned to the IL-2 arm who interrupted ART were also required to discontinue IL-2 for the same period. MAIN OUTCOME MEASURES: The primary endpoint was a decrease in CD4 T-cell count from baseline; the safety analysis was based on change in plasma HIV RNA by bDNA; and clinical safety and tolerability were analyzed by standard clinical criteria. RESULTS: Of the patients with a baseline CD4 T-cell count recorded, 15 (27%) of 55 patients randomly assigned to ART alone had a drop of > or =25% in their CD4 T-cell count and 23 (41%) of 56 patients randomly assigned to ART + IL-2 had a drop of > or =25% in their CD4 T-cell count at some time over the 24 weeks of the study. This difference was not statistically significant. There was a statistically significant greater variance in CD4 T-cell counts in the IL-2-treated group. More patients in the IL-2 group had at least a 25% increase in CD4 T-cell counts over baseline (34 vs. 13%, P = 0.007). A comparison of grade 3 or worse toxicity showed no differences between the arms, but IL-2 was associated with significantly more grade 2 or worse general body symptoms, primarily discomfort and fatigue. There was no significant difference between the groups with regard to changes in plasma HIV RNA, lymphocyte proliferation, natural killer cell activity, skin test responses to recall antigens, or antibody responses to immunization. Plasma markers of immune activation all increased significantly in IL-2 recipients. CONCLUSIONS: In patients with baseline CD4 T-cell counts > or =300 cells/mm primarily treated with single- or dual-nucleoside ART, subcutaneously administered IL-2 at a dose of 1 million IU daily for up to 24 weeks had low toxicity but showed no consistent benefit in preventing decline in CD4 T-cell counts and minimal evidence of immunologic improvement vs. continued ART alone.     

Cell-mediated immunity to cytomegalovirus (CMV) and herpes simplex virus (HSV) antigens in the acquired immune deficiency syndrome: Interleukin-1 and interleukin-2 modifyin vitro responses

Peripheral blood lymphocytes (PBL) were obtained from five patients with the acquired immune deficiency syndrome (AIDS), six homosexual males with lymphadenopathy, and five normal heterosexual controls. Modulation of virus-specific immunity was assayedin vitro by measuring the lymphocyte blastogenic response and the production of lymphokine (leukocyte inhibition factor; LIF) by PBL stimulated with herpes simplex virus (HSV) or cytomegalovirus (CMV) antigens in the presence or absence of interleukin-1 (IL-1) and interleukin-2 (IL-2). PBL from the control and lymphadenopathy subjects responded to both antigens in the lymphocyte transformation assay (LT) measured on day 7, and the responses were significantly enhanced in cultures grown in the presence of antigen and IL-2 (1 U/ml). PBL from the AIDS patients were unresponsive, but responsiveness was restored by the addition of IL-2. The addition of IL-1 (0.02 µg/ml) to antigen-stimulated PBL cultures failed to enhance the proliferative responses in all three study groups. LIF production was assayed in the supernatants from day 1 PBL cultures. LIF was not produced by PBL from AIDS patients grown in the presence of viral antigens, whereas three of five patients from the lymphadenopathy group, and three of five control subjects gave rise to positive responses. The addition of IL-1 to the antigenstimulated cultures enhanced LIF production in the control and lymphadenopathy groups but not in the AIDS patients. The addition of IL-2 did not modulate LIF production by antigen-stimulated PBL from the control oR AIDS patients while suppressing the LIF response of the similarly stimulated PBL from the lymphadenopathy patients.     

Adoptive immunotherapy with IL-2 results in the loss of delayed-type hypersensitivity responses and the development of immediate hypersensitivity to recall antigens

Skin testing represents a direct method of assessing immune responses in vivo. Twenty-six patients with metastatic cancer of the lung, kidney, or melanoma were treated with adoptive transfers of autologous tumor-infiltrating or blood lymphocytes and continuous infusions of interleukin-2 (IL-2). Prior to therapy, cutaneous anergy to recall antigens was observed in 19 patients (73%), whereas 6 (27%) displayed normal delayed-type hypersensitivity (DTH) responses. When tested again at the end of therapy, DTH responses could not be elicited in any of the patients. Proliferative responses to skin test antigens, lectins, and IL-2 diminished progressively during therapy but returned to baseline values at 1 month. Unexpectedly, 14 of these patients (53%) developed immediate skin test responses to candida antigens and 5 (19%) to mumps antigens. These immediate responses were characterized by local erythema and induration that developed within minutes of injecting antigen. Biopsies displayed marked dermal edema and infiltration by eosinophils. Although serum IgE levels were not increased, immediate reactivity could be transferred by a heat-sensitive serum factor. The implications of this novel response are uncertain, and its development did not correlate directly with the anti-tumor effects of therapy. We conclude that adoptive immunotherapy with IL-2 produces a reduction in cutaneous DTH and diminished responses to mitogens while simultaneously promoting cutaneous allergy. We hypothesize that this may reflect diminished IL-2 production by antigen-specific helper T cells and that other lymphokines may promote these immediate hypersensitivity responses.     

Lack of Response to HBHA in HIV‐Infected Patients with Latent Tuberculosis Infection

Heparin‐binding haemagglutinin (HBHA) has been proposed as an immunological biomarker for discriminating active tuberculosis (TB) from latent TB infection (LTBI) and to identify those at higher risk of progressing to active disease. Few data are available in immune‐compromised patients, which are those with increased risk of TB reactivation. The aim of this stusy was to evaluate the immune response to HBHA in HIV‐infected subjects with LTBI (HIV‐LTBI) or active TB (HIV‐TB) in comparison with the immune response to additional Mycobacterium tuberculosis (Mtb) or HIV and CMV antigens. The responses are evaluated in relation to TB status and in the LTBI subjects with the progression to active TB within 2 years. Forty‐one HIV‐infected antiretroviral‐naïve subjects were prospectively enrolled: 18 were HIV‐TB and 23 HIV‐LTBI. Whole blood was in vitro stimulated overnight with several antigens and mitogen. Interferon‐γ response in the harvested plasma was evaluated by ELISA. Despite that CD4 cell count was significantly different between HIV‐LTBI and HIV‐TB, no differences were observed in response to Mtb‐ or HIV‐specific antigens. Differently, low responses to HBHA were observed in both HIV‐LTBI and HIV‐TB subjects. Importantly, none of the six HIV‐LTBI responding to HBHA developed TB, while two of 17 non‐HBHA responders developed active disease. HIV‐TB‐coinfected subjects, regardless of their TB status, showed low responses to HBHA despite maintaining detectable responses to other antigens; moreover, among the HIV‐LTBI, the lack of HBHA responses indicated an increased risk to develop active TB. These results, although preliminary, suggest that a positive response to HBHA in HIV‐LTBI correlates with Mtb containment.     

Effects of systemicin vivo interleukin-2 (IL-2) reconstitution in patients with acquired immune deficiency syndrome (AIDS) and AIDS-related complex (ARC) on phenotypes and functions of peripheral blood mononuclear cells (PBMC)

In the context of a clinical phase I/II therapy study with recombinant interleukin-2 (rIL-2), we monitored immunological alterations in four patients with acquired immune deficiency syndrome (AIDS) and three patients with AIDS-related complex (ARC). By determining the surface phenotypes andin vitro functions of peripheral blood mononuclear cells (PBMC) before, during, and after treatment with rIL-2, we observed transient changes in all important leukocyte subpopulations, a minor restoration of immune reactivityin vitro, and an improvement in skin reactivityin vivo. In particular, we found (i) a transient increase in C3b receptor-mediated monocyte activation in ARC patients; (ii) no influence of therapy on the otherwise intact LPS-induced interleukin-1 productionin vitro; (iii) in some patients a transient corrective influence on the high pretherapeutic immunoglobulin secretion of B cells and their nonresponsiveness to pokeweed mitogen; (iv) low T-cell responses to soluble antigens and alloantigens, which were partially restored during rIL-2 treatment in ARC patients and in one AIDS patient; (v) defective NK activity in PBMC of two AIDS patients, which was found to be restored when measured at the end of rIL-2 therapy; and (vi) a rather constant phenotypic pattern of PBMC in each patient during therapy except for the decreasing proportion of OKT9-positive lymphocytes in AIDS patients, the increasing proportion of Leu8^–Leu3a⁺ lymphocytes in all patients, and in particular, the transient significant decrease in the Leu7⁺/OKT3⁺ ratio, which pretherapeutically was very high in AIDS patients (0.78±0.21) and high in ARC patients (0.48±0.06) as compared to healthy controls (0.18±0.08).Dedicated to Prof. Dr. Dr. h. c. Otto Westphal, who continuously supported and encouraged cooperation of basic and clinical immunologists.     

HIV I Infection of Dendritic Cells

Dendritic cells (DC) from human peripheral blood are susceptible to productive and probably to latent infection with HIV-I [18, 29]. Infection of DC also occurs in vivo since in HIV-seropositive individuals Langerhans’ cells of the skin [16] and DC from peripheral blood ([17], in preparation) are infected. In peripheral blood 3–25% of DC, identified as large, low-density cells lacking monocyte markers, are infected as judged by in situ hybridization with an HIV probe. This contrasts with the lower proportion (<0.2%) of other cells infected. DC exposed to HIV in vitro or in vivo fail to present other antigens or mitogens to stimulate T cells [29, 38, 41]. This functional defect in infected DC is not blocked by the presence of soluble CD4 antigen and occurs in the absence of T cell infection suggesting a block at the level of the antigen-presenting cell itself. Infection, depletion and dysfunction of DC in HIV seropositive patients is already present in asymptomatic individuals and this precedes the appearance of T cell defects. We speculate that loss of functional DC may be a fundamental defect leading to a block in recruitment of resting T cells into immune responses.

In contrast to the HIV-induced impairment of antigen presentation by DC, these cells were potent stimulators of responses to the HIV antigens themselves. Normal DC infected with HIV in vitro stimulated primary proliferative and cytotoxic T cell responses ([52], in preparation). These were produced in cells from individuals expressing a range of different MHC types but the cytotoxic cells, once produced, killed autologous but not allogeneic, infected T cell blasts. Primary response to viral peptides can also be produced suggesting that this system may be useful for identifying immunogenic epitopes of HIV using cells from sero-negative, non-immunocompromised individuals.     

Interleukin-2 correction of defectivein vitro T-cell mitogenesis in patients with common varied immunodeficiency

We studied the ability of phytohemagglutinin (PHA) and two anti-T-cell monoclonal antibodies, OKT3 and Pan T2, to induce interleukin-2 (IL2) production and proliferation in peripheral blood lymphocytes (PBL) from 14 patients with combined varied immunodeficiency (CVI). The median values of endogenous IL2 produced by mitogen-stimulated PBL was significantly lower in patients than controls irrespective of the mitogen used. The patients, taken as a group, had a significantly decreasedin vitro PBL response to mitogen stimulation when compared to controls. With the addition of a highly purified human IL2 preparation, the proliferative response in the majority of patients was significantly improved with all mitogens. Three patient groups could be distinguished: Group A (3/14) had full restoration of proliferative response with the addition of IL2, Group B (5/14) had partial restoration, and Group C (6/14) had no significant response. The monoclonal antibody, Pan T2, recognized a T-cell proliferative defect in 5 of 14 patients which neither PHA nor OKT3 recognized. This was not significantly corrected by the addition of IL2. This T-cell proliferative defect correlated with the lack of B-cell proliferation and immunoglobulin production in response to B-cell mitogens in three-fourths of the patients assayed. These data show that CVI patients are a heterogeneous group but have in common a decreasedin vitro production of IL2 resulting in a proliferative defect which is correctable at least in part,in vitro, in the majority by the addition of purified IL2.     

Immunologic effects of interleukin-2 adoptive immunotherapy in humans: acute in vitro anergy, in vivo antibody response to tetanus

In a previous study we evaluated the in vitro immunologic responses of 14 patients receiving immunotherapy with either interleukin-2 (IL-2; 3 x 10(6) units/m2) or IL-2 plus lymphokine-activated killer (LAK) cells over a 45-day period. Blastogenic responses to mitogens or antigens were found to significantly decrease. Pokeweed mitogen immunoglobulin production decreased or showed no change. Multitest skin test response decreased during and after therapy. We concluded that, although natural killer and LAK activity are enhanced during therapy, in vitro blastogenic or immunoglobulin tests using mitogens or antigens for patients undergoing IL-2 immunotherapy have no predictive values and are depressed. In this study, we provide information that patients while receiving IL-2/interferon-alpha immunotherapy demonstrate as in the previous study in vitro reduced immunologic responses by at least 60%; however, in vivo, they had a normal immunoglobulin response to a tetanus booster. The disparity in results (in vitro versus in vivo) is unexplainable. Further analysis of other in vitro and/or in vivo tests is required to determine the effect IL-2 immunotherapy may have on the immune response status.     

Immune responses in humans while receiving adoptive immunotherapy with recombinant interleukin-2 and lymphokine-activated killer cells: acute anergy to mitogens and recall antigens

In this study we evaluated the in vitro immunologic responses of 11 patients receiving immunotherapy with either interleukin-2 (IL-2, 3 X 10(6) units/m2) or IL-2 plus lymphokine-activated killer cells (LAK) over a 30-day period. Blastogenic responses to mitogens or recall antigens were found to significantly decrease during therapy. Pokeweed mitogen immunoglobulin (Ig) production decreased significantly in 7 patients or showed no change. In vivo skin tests for cell-mediated immunity were also performed and the average number of positive responses before IL-2/LAK therapy decreased to no positive responses (day 29 of therapy). Experiments were performed to determine whether decreased responses were a result of active suppression or a dilution effect by immature/mature cells that cannot respond to mitogen or antigen. Pre-therapy cells were mixed with fresh autologous (anergic) cells from day 29 of therapy in varying ratios. Blastogenesis and Ig production was measured. Our findings demonstrate that the decreased immune response observed during and after therapy is a result not of active immunosuppression but rather of a dilution effect by cells with immune dysfunction. We conclude that: (1) in vitro blastogenesis or Ig production tests using mitogens or antigens for patients undergoing IL-2 immunotherapy have no predictive value, and (2) the immune cells that are present are refractory.     

Immunological functions and phenotypes of peripheral blood lymphocytes from human T-Cell leukemia virus-I carriers

We studied immunological functions of peripheral blood lymphocytes (PBL) from human T-cell leukemia virus type I (HTLV-I)-seropositive healthy carriersin vitro. Proliferative responses of PBL to T-cell and B-cell mitogens such as concanavalin A (Con A), pokeweed mitogen (PWM), andStaphylococcus aureus Cowan I (SAC) were moderately impaired in HTLV-I carriers compared with normal controls. Immunoglobulin (Ig)-producing activity of PBL stimulated with B-cell mitogens were also impaired in HTLV-I carriers. However, cytotoxic T-cell activity induced byin vitro culture was not impaired but slightly increased in HTLV-I carriers. Natural killer-cell activity was only slightly decreased. By a flow cytofluorometric analysis of the cell surface phenotypes of PBL, the percentage and the mean fluorescence intensity (MFI) of CD 3-positive cells and CD 4-positive cells were significantly decreased in HTLV-I carriers. The percentage and the MFI of CD 8-positive cells was not changed. The percentage and the MFI of CD 25-positive cells were increased. These results suggest that some immunological abnormalities are already present in HTLV-I carriers and such abnormalities have some roles for the leukemogenesis from the infection of the HTLV-I into adult T-cell leukemia (ATL).     

Relation of impaired lymphocyte proliferative function to other major human immunodeficiency virus type 1-induced immunological changes.

Human immunodeficiency virus (HIV) type 1 (HIV-1) induces impairment of immune function reflected in reduced lymphocyte proliferative responses. Many other immune changes are induced by HIV-1, but their relationship to lymphocyte functional defects is not known. The present study was designed to correlate functional defects with other HIV disease parameters. Cryopreserved samples from 118 HIV-1-positive subjects and 40 seronegative individuals were examined. The main findings were that impaired proliferative responses to mitogens correlated with (i) decreased cell surface expression of the interleukin-2 receptor (CD25), (ii) increased expression of HLA-DR antigens on CD4 cells, (iii) reduced CD4 and increased CD8 cell numbers, and (iv) increased levels of serum immune complex dissociated p24 antigen. However, impaired function was not associated with increased serum neopterin, beta2-microglobulin, or soluble interleukin-2 receptor or with CD38 antigen expression on lymphocytes. In summary, proliferative functional impairment correlated with some, but not all, immunological changes associated with HIV-1 infection. Most of the phenotypic markers that correlated with altered function are cell surface molecules with significant roles in lymphocyte proliferation and were associated primarily with CD4 cells, compatible with the view that dysregulation of CD4 cells is responsible for impaired function.     

Enhancement by Muramyl Dipeptide of in vitro Nude Mice Responses to a T-Dependent Antigen

N- acetyl-muramyl-L-alanyl-D-isoglutamine (referred to as MDP for muramyl dipeptide) has been shown to enhance in vivo and in vitro immune responses to various antigens. It has previously been reported that in the case of T-de pendent antigens, the adjuvant: activity of MDP was mediated by a helper T-cell. Our present findings demonstrate that in vitro responses of nude mice spleen cells to T - independent, TNP-PAA or T-dependent SRBC can also be markedly increased by this synthetic adjuvant. Moreover, under the same conditions, MDP produced polyclonal activation.