Secondary immune amplification following live poliovirus immunization in humans

Eight subjects inoculated orally with live attenuated poliovirus were investigated to study the effects of live virus infection on human T-cell responses. Proliferation to poliovirus and unrelated recall antigens were measured serially over a 3-week period. Five of eight subjects inoculated demonstrated a clear anamnestic response to poliovirus, but three did not. Only the five subjects demonstrating an anamnestic response to poliovirus were found to have augmented secondary immune responses to two unrelated recall antigens (tetanus toxoid and reovirus) and in the autologous mixed lymphocyte response (AMLR). No consistent changes were found in circulating T-cell surface activation antigens whether or not the subjects responded to poliovirus. These studies suggest that an asymptomatic poliovirus infection associated with immunization in humans can induce nonspecific secondary immune amplification as measured by in vitro T-cell proliferative response. This amplification pathway is a potential mechanism for immune responses against antigens other than those of the infecting virus.     

Decreased antibody response following immunization with enantiomorphic synthetic polypeptides

The ability to decrease the antibody response to poly(Glu52Lys33Tyr15) in the DA and PVG strains of rats by prior immunization with its D-amino acid enantiomorph poly(DGlu48DLys38DTyr14) was tested as part of a continuing investigation into the role of optical isomerism in the ability of an antigen to induce an antibody response. The results showed that prior immunization with the D-amino acid polymer decreased the immune response to the isomeric L-polypeptide in both strains.     

Differential migration of helper and precursor spleen cells following immunization

Immunization with bovine serum albumin (BSA) results in a population of “helper” cells, as well as antibody-forming cell precursors (AFCP). Helper cells may assist AFCP to make antibody directed at some determinant on the protein molecule, including artifically added haptens. When spleen cells containing both these cell populations were passaged into irradiated recipients, the lymph node-seeking cells were found to be enriched in “helper” activity and depleted of AFCP activity. This difference in the migratory properties of “helper” cells and AFCP may be exploited t o achieve relatively pure populations of “helper” cells.     

Secretory immunity induced in catfish, , following bath immunization

Individual adult channel catfish were immunized by immersion in an antigen bath containing dinitrophenylated-horse serum albumin. Anti-DNP hemagglutination titers of serum and cutaneous mucus were determined following both primary and secondary bath immunization. The results showed that five of the six fish had a cutaneous mucosal anti-DNP titer following the bath immunizations. In contrast, only one of the six catfish was shown to have any demonstrable change in its serum anti-DNP titer following the bath immunizations. The mucous anti-DNP hemagglutinin was shown to be antibody (Ab). The affinity-purified mucous Ab was found to have the same complex tetrameric architecture as well as the same molecular weight heavy and light chains as serum anti-DNP Ab. Histological studies showed that the catfish epidermis was richly vascularized. Within the epidermis there were numerous lymphocytes which were predominantly associated with the basal layer. These studies indicate that the secretory immune system of catfish can be stimulated by external antigens. Secondly, these studies show that bath immunization can differentially effect the relative antibody response of the catfish secretory and systemic immune systems.     

Active protection against rotavirus infection of mice following intraperitoneal immunization.

Active immunity to rotavirus has been demonstrated following oral inoculation with live virus but little is known about the effects of parenteral immunization. In this study, adult mice were immunized by intraperitoneal (ip) inoculation with live rotaviruses and later orally challenged with murine rotavirus (EDIM) to measure active immunity against infection. Three doses of EDIM (8 micrograms/dose) given intraperitoneally (ip) provided full protection against EDIM infection, whether administered with or without Freund's adjuvant. Only partial protection was found when the quantity of immunogen was reduced to < 2 micrograms/dose. Reduction of the number of doses from three to one (8 micrograms/dose), however, still resulted in protection of all mice. Significant protection was also observed after inoculation with one or three doses (2 micrograms/dose) of heterologous rotaviruses. Protection provided by the heterologous strains did not correlate with neutralizing antibody to EDIM, which indicated that neutralizing antibody to the challenge virus was not required for protection. uv-Inactivated EDIM also provided significant protection against EDIM, thus demonstrating that viral replication was not required for protection. These results suggest that parenteral immunization may be an effective method to vaccinate against rotavirus disease.     

Transient decreases in human T cell proliferative responses following vaccinia immunization

To further study the immunosuppression associated with virus infections, we analyzed the proliferative responses of serial PBMC samples obtained following vaccinia virus immunization. In four of five volunteers, responses to PHA, anti-CD3, vaccinia virus, and recall antigens were markedly decreased at at least one time point between days 5 and 29 after vaccination. Responses to PHA were restored by the addition of IL-2 or irradiated autologous healthy PBMC in the two volunteers tested, suggesting that the proliferation defect is attributable to accessory cell dysfunction. In one donor, immobilized anti-CD3 failed to induce proliferation, but addition of immobilized anti-CD28 partially restored proliferation. These results indicate that vaccinia virus infection can transiently suppress proliferative responses of PBMC, in part by causing accessory cell dysfunction. Our findings extend the list of viral infections associated with systemic immunologic effects and demonstrate that suppression of proliferation can occur with localized virus infections.     

Neuropathology and pathogenesis of encephalitis following amyloid-beta immunization in Alzheimer's disease

Immunizing transgenic PDAPP mice, which overexpress mutant APP and develop beta-amyloid deposition resembling plaques in Alzheimer's disease (AD), results in a decrease of amyloid burden when compared with non-treated transgenic animals. Immunization with amyloid-beta peptide has been initiated in a randomised pilot study in AD. Yet a minority of patients developed a neurological complication consistent with meningoencephalitis and one patient died; the trial has been stopped. Neuropathological examination in that patient showed meningoencephalitis, and focal atypically low numbers of diffuse and neuritic plaques but not of vascular amyloid, nor regression of tau pathology in neurofibrillary tangles and neuropil threads. The present neuropathological study reports the second case of meningoencephalitis following immunization with amyloid-beta peptide in AD, and has been directed toward exploring mechanisms underlying decreased tau pathology in relation with amyloid deposit regression, and possible molecular bases involved in the inflammatory response following immunization. Inflammatory infiltrates were composed of CD8+, CD4+, CD3+, CD5+ and, rarely, CD7+ lymphocytes, whereas B lymphocytes and T cytotoxic cells CD16, CD57, TIA and graenzyme were negative. Characteristic neuropathological findings were focal depletion of diffuse and neuritic plaques, but not of amyloid angiopathy, and the presence of small numbers of extremely dense (collapsed) plaques surrounded by active microglia, and multinucleated giant cells filled with dense Abeta42 and Abeta40, in addition to severe small cerebral blood vessel disease and multiple cortical hemorrhages. Reduced amyloid burden was accompanied by low amyloid-associated oxidative stress responses (reduced superoxide dismutase-1: SOD-1 expression) and by local inhibition of the stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) and p38 kinase which are involved in tau phosphorylation. These results support the amyloid cascade of tau phosphorylation in AD regarding phosphorylation of tau dependent on beta-amyloid deposition in neuritic plaques, but not of tau in neurofibrillary tangles and threads. Furthermore, amyloid reduction was accompanied by increased expression of the PA28a/beta inductor, and of LMP7, LMP2 and MECL1 subunits of the immunoproteasome in microglial and inflammatory cells surrounding collapsed plaques, and in multinucleated giant cells. Immunoproteasome subunit expression was accompanied by local presentation of MHC class I molecules. Release of antigenic peptides derived from beta-amyloid processing may enhance T-cell inflammatory responses accounting for the meningoencephalitis following amyloid-beta peptide immunization.     

Inflammatory response and antigen localization following immunization with influenza virus ISCOMs

The inflammatory response, antigen retention, and antigen localization was studied in mice after immunization with influenza virus glycoproteins presented in two physically defined forms-micelles and ISCOMS (immunostimulating complexes). Two hours after intraperitoneal injection, the proportion of polymorphonuclear leukocytes (PMNs) in peritoneal lavage cells increased from less than 1% to 82% in ISCOM-treated mice and from <1% to 41% of the total cell count in micelle-treated mice. For both treatment groups, the proportion of PMNs returned to around zero 24 h postimmunization. Total recovery of radioactive antigen was significantly greater (P<0.05) in ISCOM-treated than in micelle-treated mice at one, two, and eight days postinjection. At all times tested, animals given ISCOMs had significantly more radioactive antigen in their spleens than animals given micelles. By electron microscopy ISCOMs were found to attach externally to the plasma membrane or within phagosomes of macrophages in close association with the membranes.     

Age-dependent antibody response in mice and humans following oral influenza immunization

In order to compare the antibody response in serum and secretions from healthy young subjects and the elderly (>60 years), volunteers were immunized with the commercial inactivated influenza virus vaccine, by the usual (parenteral) route or orally. Also, young and old mice (mean age, 20 months) were orally immunized with live influenza virus. The older mice responded with a very slight rise in their serum and respiratory tract antibody levels compared with the young mice but showed no diminution in protection against lethal viral challenge. Elderly volunteers showed only slight serum antibody responses after parenteral immunization compared with the young. Neither group demonstrated a rise in serum antibody following oral immunization. With respect to the secretory IgA (SIgA) antibody response, certain differences were noted between the young and the elderly: the preimmunization levels of antibody to influenza virus were significantly greater in nasal secretions and saliva in the elderly as compared to the young volunteers, and the salivary antibody response was diminished in the elderly. This lack of a salivary antibody response in the elderly was explicable by the inverse relationship between the preimmunization SIgA antibody titers and the response to immunization. Oral immunization led to no more side effects than observed in the placebo control group.     

Kinetics of specific in vitro antibody production following influenza immunization.

In vitro specific antibody responses to influenza viral antigens by peripheral blood mononuclear leucocytes following stimulation with influenza virus or pokeweed mitogen have been measured before and at time intervals after influenza immunization in 11 healthy volunteers. There was an early increase in specific antibody produced by lymphocytes stimulated with influenza virus in vitro, in all subjects immunized. The magnitude of the response varied considerably between individuals as did its duration. Virus specific antibody production by cells stimulated with pokeweed mitogen also increased after immunization in all donors. Cells from six of the 11 individuals produced specific antibody in vitro seven days after immunization without antigen or mitogen stimulation. Seven of the 11 subjects had a greater than four-fold increase in serum titre of haemagglutination inhibiting antibody. This study shows an early brisk increase in the ability of lymphocytes to respond to influenza virus in vitro following immunization consistent with a secondary immune response.     

Antipeptide antibody responses following intranasal immunization: effectiveness of mucosal adjuvants

Toxicity is a major factor limiting the development and use of potent adjuvants for human mucosally delivered vaccines. Novel adjuvant formulations have recently become available, and in the present study two have been used for intranasal immunization with a synthetic peptide immunogen (MAP-M2). This peptide represents a multiple antigenic peptide containing multiple copies of a mimotope M2, a peptide mimic of a conformational epitope of the fusion protein of measles virus. MAP-M2 was administered intranasally to experimental animals together with synthetic oligodeoxynucleotides containing unmethylated CpG motifs with or without a mutant of wild-type enterotoxin of Escherichia coli (LTR72). The combination of the mutant toxin LTR72 and the CpG repeats, codelivered with a peptide immunogen, induced both local and systemic peptide- and pathogen-specific humoral and cellular immune responses comparable to those obtained after intranasal immunization with the wild-type toxin LT. In addition, this combination of adjuvants induced a predominantly immunoglobulin G2a antibody response. If both the LTR72 and CpG adjuvants are shown to be safe for use in humans, this particular combination would appear to have potential as an adjuvant for mucosally delivered vaccines in humans.     

Local and systemic immune responses following oral immunization of foetal lambs.

Foetal lambs were immunized orally 6-15 days before birth by introducing horse spleen ferritin into the amniotic fluid. Immunized and non-immunized lambs were killed at birth, usually before they had suckled, blood and intestinal contents were collected and single cell suspensions were prepared from spleen, mesenteric lymph nodes and jejunum. Specific antibody was detected in serum and intestinal contents of all immunized lambs which had not suckled. Specific antibody was usually not detected in samples from non-immunized lambs. In immunized lambs antibody activity in serum was associated with IgM and in intestinal contents with IgA and IgM. In agreement with these findings, the levels of IgM and IgA in serum and intestinal contents of immunized lambs were relatively high. Generally, immunoglobulins were not detected in samples from non-immunized lambs. Relatively high proportions of cells secreting specific antibody were present in the tissues of immunized but not non-immunized lambs. In the spleen most of the cells were secreting IgM antibody, in mesenteris lymph nodes IgM cells predominated and small numbers of IgA cells were detected, and in the jejunum approximately equal numbers of IgA and IgM cells were secreting specific antibody.     

Activation of cell-mediated immunity following immunization with pneumococcal conjugate or polysaccharide vaccine

The immunogenicity of pneumococcal polysaccharide (PS) vaccines can be improved by conjugating PS to a polypeptide carrier that alters the immune response from T-cell independent to T-cell dependent. In order to study the influence of PS or protein antigens as inducers of cell-mediated responses, 30 adults were immunized with a 23-valent pneumococcal PS vaccine (PS-group) or an 11-valent, tetanus and diphtheria mixed carrier conjugate vaccine with (adjuvant group) or without aluminium adjuvant (nonadjuvant group). Cell-mediated responses were analyzed on days 0, 14 and 28 after vaccination by measuring lymphocyte proliferation and production of interferon (IFN)-gamma (Th1 marker) or interleukin (IL)-4 and IL-5 (Th2 markers) cytokines after in vitro stimulation with the PS and protein components of the vaccines. Tetanus and diphtheria proteins were the main inducers of lymphocyte proliferative and cytokine responses. Conjugate vaccines induced increased proliferative responses to the tetanus or diphtheria protein, but not to the PS components. In the PS-group, a lymphocyte proliferative response to protein antigens was not observed. The number of antigen-specific and nonspecific IFN-gamma-secreting cells detected by ELISPOT tended to increase in all three groups in response to protein or to PS antigen. No major differences were detected in the number of IL-4-secreting cells measured 14 and 28 days after vaccination. The conjugate vaccine with adjuvant was associated with Th2 type of activation indicated by an enhanced IL-5 secretion in response to the tetanus and diphtheria protein antigens.     

Acute lethal toxicity following passive immunization for treatment of murine cryptococcosis.

Passive immunization with monoclonal antibodies (MAbs) specific for the major capsular polysaccharide of Cryptococcus neoformans alters the course of murine cryptococcosis. During studies of passive immunization for treatment of murine cryptococcosis, we noted the occurrence of an acute, lethal toxicity. Toxicity was characterized by scratching, lethargy, respiratory distress, collapse, and death within 20 to 60 min after injection of antibody. The toxic effect was observed only in mice with a cryptococcal infection and was reduced or absent in the early and late stages of disease. The clinical course and histopathology were consistent with those for shock. There was considerable variation between mouse strains in susceptibility to toxicity. Swiss Webster mice from the Charles River colony were most susceptible, followed by C3H/He, BALB/c, and C57BL/6 mice. DBA/2 mice and Swiss Webster mice from the Simonsen colony were resistant. Acute toxicity was mimicked by injection of preformed complexes of MAb and purified polysaccharide. The toxic effect was also produced by injection of MAbs into mice that were preloaded with polysaccharide. The toxic effect was not blocked by treatment of mice with chloropheniramine or anti-tumor necrosis factor alpha antibodies or by depletion of complement components via pretreatment with cobra venom factor. Toxicity was reduced by treatment of mice with high doses of epinephrine, dexamethasone, or chlorpromazine. Finally, the toxic effect was completely blocked by treatment of mice with the platelet-activating factor antagonist WEB 2170 BS or by pretreatment of mice with the liposome-encapsulated drug dichloromethylene diphosphonate, a procedure which depletes macrophages from the spleen and liver.