A recombinant Leishmania chagasi antigen that stimulates cellular immune responses in infected mice.

Cellular immune mechanisms resulting in gamma interferon production are critical for protection against visceral leishmaniasis. Antigens stimulating T-cell responses are likely present in the intracellular amastigote form of the parasite, since this is the form found in a mammalian host. To identify T-cell antigens of Leishmania chagasi, the parasite causing South American visceral leishmaniasis, we used a double antibody-T-cell technique to screen an amastigote cDNA library. One cDNA selected (Lcr1) encodes an antigen that stimulated proliferation of splenic T lymphocytes from infected mice that were either resistant (C3H.HeJ) or susceptible (BALB/c) to L. chagasi infection. The Lcr1 cDNA contains four highly divergent 201-bp repeats homologous to the 204-bp repeat of a Trypanosoma cruzi flagellar antigen gene. Results are consistent with a single copy of the Lcr1 gene producing an mRNA of > 10 kb and a protein of > 200 kDa. Recombinant Lcr1, cloned adjacent to polyhistidine and purified on a nickel affinity column, stimulated gamma interferon but not interleukin-4 (IL-4), IL-5, or IL-10 secretion by T-cell-enriched splenocytes from either susceptible or resistant mice during L. chagasi infection. Immunization with Lcr1 partially protected BALB/c mice against challenge with L. chagasi, indicating the utility of the double screening approach in selecting relevant T-cell antigens.     

Impairment of cellular but not humoral immune responses in chronic pulmonary and disseminated paracoccidioidomycosis in mice.

Humoral and cellular immune responses were measured during the progression of chronic pulmonary and disseminated paracoccidioidomycosis in mice. The chronic disease was established by pulmonary infection of mice with different doses of the yeast form of Paracoccidioides brasiliensis isolate GAP. Levels of antibodies to P. brasiliensis, detected in serum by immunodiffusion and enzyme-linked immunosorbent assay, directly correlated with the size of the infectious challenge. Significant delayed-type hypersensitivity (DTH) responses to antigen were largely restricted to week 1 after pulmonary infection with intranasally administered high doses (5.0 x 10(6) or 1.1 x 10(7) CFU per inoculum). In vitro lymphoproliferative responses of peripheral blood lymphocytes (PBL) to P. brasiliensis antigens were significant only at 2 weeks after infection with intranasally administered 1.1 x 10(7) CFU. Responses of PBL to concanavalin A were depressed (50% of control response) as early as 8 weeks and reached a nadir at 10 to 18 weeks after infection. Infected mice made antibodies to sheep erythrocytes (SRBC) (10(9) intravenously [i.v.]) normally at all times tested after infection. In contrast, infected mice sensitized to SRBC (10(6) i.v.) had significantly depressed DTH responses to SRBC at 9 and 20 weeks postinfection compared with noninfected mice. These results indicated that in this model, normal humoral responses developed to homologous and heterologous antigens. In contrast, the T cellular immune responses were depressed with progression and chronicity of the disease. Thus, this model closely mimics the immunological findings in human paracoccidioidomycosis.     

Modulation of immune responses in newborn and adult mice by interferon.

Interferon was found to have both suppressive and enhancing effects on the antibody response in newborn and adult mice. Evidence was obtained that these effects are primarily evoked during the initial steps controlling cell proliferation. Stimulation of thymus and spleen cells with a T-cell mitogen was enhanced by low doses and suppressed by high doses of interferon. Treatment of parental spleen cells with interferon before injecting them into immunized F1 hybrid mice resulted in an enhanced allogeneic effect. These results are compatible with the hypothesis that interferon affects T cells and has an immunoregulatory role, either by inhibiting the action of suppressor cells or by promoting immunological maturation.     

Pharmacological modulation of suppressor cell activity in mice with disseminated histoplasmosis.

Indomethacin and cyclophosphamide (CY) were used in an attempt to modify the suppressive effects of spleen cell populations from mice with disseminated histoplasmosis at 1 week of infection. In vitro addition of indomethacin did not alter the depressed plaque-forming cell response to sheep erythrocytes of normal spleen cells cocultured with unfractionated or nylon wool-fractionated spleen cells from infected mice. Likewise, indomethacin given intraperitoneally did not enhance the subnormal in vivo plaque-forming cell response of spleen cells from infected mice. Conversely, 20 mg of CY per kg given intraperitoneally 2 days before or 6 h after the inoculation with Histoplasma capsulatum partially reversed the suppression effected by splenic T cells (nylon wool passed) in vitro, whereas 50 mg of CY per kg given intraperitoneally 6 h after the injection of H. capsulatum ablated suppressor T cell activity in vitro; neither dosage of CY altered the suppression mediated by unseparated or nylon wool-adherent spleen cells. Furthermore, the administration of 50 mg of CY per kg failed to improve the depressed footpad responses of mice infected for 1 week to sheep erythrocytes in sheep erythrocyte-sensitized mice or to histoplasmin. These findings indicate that in experimental disseminated histoplasmosis, suppression effected by splenic T cells can be alleviated by CY; however, there is a persistent immunosuppressor mechanism(s) that cannot be counteracted by either indomethacin or CY.     

Modulation of cellular immune response by orbifloxacin in noninfected and E. coli-infected mice

The studies were conducted on noninfected and Escherichia (E) coli-infected mice treated with orbifloxacin administered orally 10 times at 24-hr intervals at a dose of 2.5 mg/kg. Orbifloxacin did not change the activity of peritoneal macrophages in noninfected mice. Administration of orbifloxacin in E. coli-infected mice modulated the effects of infection on the percentage of phagocyting macrophages, the percentage of NBT-positive cells, and nitric oxide production. Orbifloxacin did not affect the synthesis and release of interleukin-1 by macrophages. Orbifloxacin exerted a modulating effect on the subsets of lymphocytes in thymus, spleen, and mesenteric lymph node cells in noninfected and E. coli-infected mice.     

rIL-18对肺炎链球菌肺炎小鼠Th1/Th2免疫应答的影响

目的 研究重组白细胞介素18(rIL-18)对肺炎链球菌肺炎小鼠Th1/ Th2免疫应答的影响.方法 鼻腔接种肺炎链球菌建立小鼠肺炎链球菌肺炎模型,将Balb/c小鼠24只随机分为3组,分别为对照组,肺炎组和肺炎rIL-18干预组(n=8 ),RT-PCR法检测各组小鼠肺组织中IFN-γ、IL-4 mRNA 的表达,同时支气管肺泡灌洗液(BALB)进行活菌计数,有核细胞分类计数.结果 ①肺炎rIL-18干预组BA LF中性粒细胞和巨噬细胞计数显著高于肺炎组和对照组(P＜0.001);②肺炎rIL-18 干预组BALF活菌计数显著低于肺炎组(P＜0.001);③肺炎rIL-18干预组肺组织IFN- γ mRNA表达上调而IL-4 mRNA表达下调(P＜0.001).结论 在小鼠肺炎链球菌肺炎早期给予rIL-18可诱导IFN-γ的合成,促进Th1免疫应答,使Th1/ Th2免疫平衡向Th1免疫偏移、促进宿主对肺炎链球菌的防御.     

Modulation of immune responses in mice by oral administration of niflumic acid

The in vivo effects of non-steroidal anti-inflammatory drugs (NSAIDs) on the host immune system are still poorly understood. However, through inhibition of prostaglandin synthesis, NSAIDs may exhibit immunomodulating properties. The present work was aimed at evaluating the influence of niflumic acid on immune responses when administered orally for 7 consecutive days to 8-week-old inbred mice. Immunological tests were performed 24 h after the arrest of the treatment. At a dosage of 50 mg/kg/day, niflumic acid exerted noticeable immunostimulating effects, as shown by an increase in plaque-forming cell numbers after in vivo immunization with sheep red blood cells, an augmentation of spleen cell proliferation responses to stimulation with T- or B-cell mitogens and of T-cell cytotoxic response to allogenic cells. Phagocytosis-induced chemiluminescence of peritoneal macrophages was also enhanced whereas interleukin-1 production by these cells was depressed, but without concomitant modification in interleukin-2 production by T-cells. Increasing the niflumic acid dosage to 75 mg/kg resulted in the disappearance of the immunostimulatory effects on lymphocytes responses. Macrophage activities were affected similarly in mice receiving 50 mg/kg. These results demonstrate that niflumic acid is able to stimulate in vivo several immunological functions and, consequently, to maintain host immune defenses. Interestingly, it depressed interleukin-1 production, known to play a major role in the inflammatory process.     

Acceleration of IgE responses by treatment with recombinant interleukin-3 prior to infection with Trichinella spiralis in mice.

Treatment of mice with recombinant interleukin-3 (rIL-3) accelerated an IL-4-dependent IgE production following infection with Trichinella spiralis. When mice were treated with a total of 1.5 x 10(4) units rIL-3 for 5 days before infection with 400 muscle larvae, the serum IgE level increased prominently on day 5. Acceleration of IgE responses was dependent on the dose of rIL-3 injected. Treatment of mice with a total of 10(3) units rIL-3 could accelerate IgE responses. IgE responses were detected by a sandwich enzyme-linked immunosorbent assay at least from day 3 in mice treated with rIL-3. Acceleration of IgE responses was inhibited by anti-IL-4 monoclonal antibody. In contrast to this, IgG1 and IgG2a responses were not suppressed by the anti-IL-4 treatment. IL-3 treatment could up-regulate IgE and IgG1 responses but not the IgG2a response. IL-3 treatment could also accelerate IgE responses in W/Wv mice infected with the parasites. These results suggest that IL-3 is involved in regulation of IgE responses in mice and that mast cells do not play an essential role in acceleration of IgE responses induced by rIL-3 treatment in this system.     

Modulation of in vitro porcine natural killer cell activity by recombinant interleukin-1 alpha, interleukin-2 and interleukin-4.

Stimulation with lipopolysaccharide (LPS) initiated monocytes to produce interleukin-2 receptor light chain (p55 IL-2R). After stimulation with LPS for 48 hr, considerable quantities of soluble IL-2R were found in the supernatants of monocytes, exceeding even the amount of soluble IL-2R produced by activated T lymphocytes. Cell-associated p55 IL-2R was also increased during the first 24 hr of stimulation, after which time it remained constant. Fractionation of cells and analysis of cytoplasm, mitochondria, plasma membranes and nuclei for the presence of p55 IL-2R revealed that the main portion of receptor was present in the cytoplasm. This led to the conclusion that in monocytes cell-associated p55 IL-2R is not necessarily attached to membranes but is present in a soluble form in the cytoplasm, presumably freshly produced with the aim of being secreted. Stimulation of monocytes with pure recombinant interferon-gamma did not lead to augmentation of p55 IL-2R, as shown by enzyme-linked immunosorbent assay, binding of antibodies directed against the receptor (anti-Tac, CD25) and analysis of p55 IL-2R gene expression.     

Evolution of inflammatory response and cellular immune responses in a murine model of disseminated blastomycosis.

A reproducible model of disseminated blastomycosis was established in C57BL/6 mice by intravenous injection of 10(6) yeast-phase Blastomyces dermatiditis organisms. The infection progressed over 5 weeks to involve lungs, brains, superficial fascia, livers, and spleens of mice. By week 5, there was a greater number of organisms in lungs and brains than in livers and spleens. The tissue response in lungs, brains, and livers progressed from acute neutrophilic invasion before week 1 to pyogranuloma formation by week 5. Lymph nodes and spleens were remarkably spared. By week 5, infected mice became anergic to intradermal challenge with both specific Blastomyces antigen and a nonspecific antigen (sheep erythrocytes). At this time, the response to concanavalin A or phytohemagglutinin by splenocytes was markedly less than that of normal controls. Likewise, the plaque-forming cell response to sheep erythrocytes by splenocytes from infected mice was diminished. In coculture studies, splenocytes from 5-week-infected mice reduced the plaque-forming cell response by normal splenocytes. The development of this murine model should prove useful for elucidating the perturbations of immunoregulation associated with disseminated blastomycosis.     

Modulation of the immune responses against SRBC after oestriol treatment in mice.

Delayed-type hypersensitivity (DTH), primary direct and indirect PFC, memory antibody response and suppressor cell induction against sheep red blood cells (SRBC) have been examined in oestriol (E3) pretreated mice. The results showed that DTH and primary direct and indirect PFC responses were suppressed by E3 treatment. These suppressive effects could, however, be overcome when oestrogenized mice were given supra-optimal doses of SRBC for each response. On the other hand, the memory antibody response was markedly enhanced when E3 was given prior to the primary antigen stimulation. Induction of the suppressor cells for the antibody response seemed not to be affected by E3 treatment, but the characterization of the suppressor cells revealed that those obtained from E3 treated mice were surface immunoglobulin positive (sIg+) cells whereas those from control mice were not. These results were discussed in terms of the altered antigen distribution due to the activated phagocytic activity of the reticuloendothelial system (RES) after E3 treatment.     

Immunoregulatory responses in experimental disseminated histoplasmosis: depression of T-cell-dependent and T-effectory responses by activation of splenic suppressor cells.

The cellular immune responses of mice with disseminated histoplasmosis are markedly diminished in association with the generation of potent immunosuppressor activity by spleen cells. The zenith of suppressor activity was observed during most active infection, from 1 to 3 weeks after inoculation. During this time there was: (i) depression of the delayed-type hypersensitivity response to sheep erythrocytes and histoplasmin, (ii) impairment of concanavalin A- and histoplasmin-induced blastogenic transformations by splenocytes in vitro, (iii) depressed cytotoxic activity of spleen cells from infected mice, and (iv) marked suppression by splenocytes from infected mice of the primary antibody response to sheep erythrocytes by normal spleen cell cultures. With resolution of the infection by week 8, there was a shift of immunoregulatory function from dominant suppressor activity to expression of helper activity. At this time, delayed-type hypersensitivity responses to the above antigens were vigorous; furthermore, the cytotoxic activity and plaque-forming cell response of splenocytes from 8-week-infected mice were equal to or greater than normal control values. The shift in the immunoregulatory response from a suppressor to a helper mode indicated that the net amount of help or suppression measured at any given time during infection represented the algebraic sum of both helper and suppressor activities mediated by different populations or subpopulations of cells within the splenic microenvironment of infected mice.     

我国不同艾滋病候选疫苗小鼠细胞免疫应答评价

目的 比较我国不同艾滋病(AIDS)候选疫苗小鼠细胞免疫应答水平.方法 将我国6种艾滋病候选疫苗按其各自免疫程序,免疫BALB/c小鼠,分离脾细胞,利用酶联免疫斑点法(ELISPOT)与胞内因子染色法(ICS)检测其对HIV特异多肽的细胞免疫应答水平.结果 6种艾滋病候选疫苗利用潜在T细胞表位(PTE)Gag、Env和Pol肽库和ELISPOT法检测IFN-γ的分泌情况,结果各疫苗的小鼠细胞免疫阳转率为70%～100%,各疫苗引起特异细胞免疫应答的反应肽库不同,强度亦不相同.1#和2#疫苗利用ELISPOT检测分泌Th1类细胞因子IFN-γ和IL-2的小鼠脾细胞数量,两疫苗的IFN-γ和IL-2检测结果均呈中度相关性(r1=0.62,P1＜0.01;r2=0.79,P2＜0.01).ELISPOT和ICS检测1#疫苗免疫后分泌IFN-γ的小鼠脾细胞数,结果两种方法的小鼠阳转率均为66.7%(10/15),ELISPOT阳性细胞数与ICS阳性细胞比例呈中度相关(r=0.55,P＜0.05).结论 我国不同AIDS候选疫苗引起的小鼠细胞免疫应答在广度和强度上存在差别.ELISPOT或ICS检测IFN-γ等Th1类细胞因子可作为疫苗诱导小鼠细胞免疫应答的评价指标.     

Macrophage-related fibrinolysis in experimental disseminated histoplasmosis.

The nutritionally variant streptococci (NVS) are usually isolated from patients with NVS endocarditis and recently have been serotyped into three groups. In the past, studies on microbial endocarditis have not analyzed the effect of the growth medium or growth phase on the bacteria used to induce the disease in the experimental rabbit model. Therefore, in this study various bacterial growth parameters were examined, including growth in semisynthetic or complex medium to the exponential or stationary phase of growth. The 50% infective dose ranged from 3.7 X 10(5) to 8.5 X 10(6) CFU for representative strains from each of the three serotypes grown under these conditions, indicating that there was no significant difference. The role of immunization was also examined in this model using organisms grown to the exponential phase in semisynthetic medium. Rabbits were immunized with heat-killed whole cells, high titres of specific antibody were produced as demonstrated by enzyme-linked immunosorbent assay, and then the rabbits were challenged with 20- to 100-fold 50% infective dose of the homologous strain. A total of 90 to 100% of the rabbits were protected from the disease process, as shown by the absence of the organisms from the heart valve 3 days after the challenge. Rabbits immunized with the amphiphile that replaces lipoteichoic acid in these organisms were not protected from challenge, demonstrating that another surface component is responsible for adherence or colonization or both. Finally NVS were incubated with radioiodinated fibronectin, fibrinogen, or laminin to determine whether these molecules aided in the adherence of the organisms to the heart valve. Only minor amounts of these components were bound to NVS as compared with controls. Therefore, NVS bind directly to the damaged heart valve or through an unknown mechanism.     

T lymphocyte-mediated antiviral immune responses in mice are diminished by treatment with monoclonal antibody directed against the interleukin-2 receptor

Blocking the interleukin-2 receptor's α-chain in lymphocytic choriomeningitis virus-infected mice by treatment with monoclonal antibodies diminished the increase of numbers of CD8⁺ T lymphocytes in spleens and prevented CD8⁺ T lymphocyte-mediated virus clearance from organs as well as generation of virus-specific cytotoxic T lymphocytes. Also, the CD8⁺ T cell-mediated early phase of the delayed-type hypersensitivity footpad swelling reaction was decreased. The same treatment had no effect on the number of CD4⁺ spleen T lymphocytes, which, however, did not enlarge during infection, but these cells' heightened DNA synthesis and cytokine production were reduced by antibody treatment; yet the generation of antiviral antibodies remained unaffected, and the CD4⁺ T lymphocyte-mediated second part of the footpad reaction was somewhat augmented. We conclude that blocking of the interleukin-2 receptor by antibody in lymphocytic choriomeningitis virus-infected mice diminishes both CD8⁺ and CD4⁺ T cell-mediated antiviral immune responses, the former more than the latter.     

Regulation of immune responses by interleukin-27

Summary: Cytokine-mediated immunity plays a crucial role in the pathogenesis of various diseases including autoimmunity. Recently, interleukin-27 (IL-27) was identified, which, along with IL-12, IL-23, and IL-35, belongs to the IL-12 cytokine family. These family members play roles in the regulation of T helper (Th) cell differentiation. IL-27 is unique in that while it induces Th1 differentiation, the same cytokine suppresses immune responses. In the absence of IL-27-mediated immunosuppression, hyper-production of various pro-inflammatory cytokines concomitant with severe inflammation in affected organs was observed in IL-27 receptor α chain (WSX-1)-deficient mice infected with Trypanosoma cruzi. Experimental allergic or inflammatory responses were also enhanced in WSX-1-deficient mice. The immunosuppressive effects of IL-27 depend on inhibition of the development of Th17 cells (a newly identified inflammatory T-helper population) and induction of IL-10 production. Moreover, administration of IL-27 or augmentation of IL-27 signaling suppresses some diseases of autoimmune or allergic origin, demonstrating its potential in therapy of diseases mediated by inflammatory cytokines. In this review, we discuss recent studies on the role of IL-27 in immunity to parasitic and bacterial infections as well as in allergy and autoimmunity in view of its pro- and anti-inflammatory properties.     

Phase I trial with recombinant interleukin-2 (rIL-2): immune activation by rIL-2 alone or following pretreatment with recombinant interferon-gamma.

Alterations of immunological parameters were analysed in patients with advanced malignancies during a phase I trial with rIL-2. Five-day infusions of rIL-2 at doses from 1 x 10(6) to 24 x 10(6) biological response modifiers program (BRMP) U/m2 per day were given to 29 patients, with a minimum of three patients per dose. The dose of 24 x 10(6) U/m2 per day was the maximal tolerated dose (MTD). Immunological parameters were analyzed at days 0, 8 and 11 of the rIL-2 courses. Following a leucopenia during rIL-2 infusion, a lymphocytosis was found in all patients except one. The lymphocytosis peaked at day 8 and was detected at doses of rIL-2 as low as 1 x 10(6) U/m2 per day, reaching a plateau at a dose of 16 x 10(6) U/m2 per day. Although all lymphocyte subsets were increased in patients receiving rIL-2, some patients had predominant T cells (CD3+, NKH1(CD56)-), others had predominant natural killer (NK) cells (CD3-, NKH1 (CD56)+), and yet others showed a mixed profile. A strong induction of cells cytotoxic for K562 targets was found in all patients at days 8 and 11. Eighteen patients received, 1 month later, a second treatment in which infusion of rIL-2 was preceded by a course of 5 days infusion of 2 x 10(6) U/m2 per day recombinant interferon-gamma (rIFN-gamma). The infusion of rIFN-gamma prior to rIL-2 had no effect on the rIL-2-induced alterations of immunological parameters. Taken together, our results suggest that immune stimulation by rIL-2 occurs even at low doses and is maximal at a dose below the MTD; and that pretreatment with low-dose rIFN-gamma does not modify the immune stimulation by rIL-2.     

Modulation of innate immune responses by hantaviruses

Hantavirus infection can cause hantavirus cardiopulmonary syndrome or hemorrhagic fever with renal syndrome depending on the virus species involved. The determinants for the virus species specific virulence in humans are unclear. Successful infection is a conditio sine qua non for the virulence of a virus and it is well-known that the innate interferon (IFN) system generally plays a decisive role to prevent establishment of an infection. The importance of the IFN system is underscored by the fact that viruses have developed an amazing number of different escape mechanisms to enable replication in face of the antiviral host response. Interestingly, pathogenic hantaviruses escape induction of innate antiviral responses in the early phase of the infection, which are elicited in a pronounced manner by nonpathogenic hantaviruses in vitro. This differential response might be important for the pathogenicity of hantaviruses in humans. This review aims to summarize the current knowledge about the interaction between hantaviruses and the innate IFN system. Detailed characterization of the cellular sensors and pathways that lead to activation of the IFN system on one side and the viral escape mechanisms on the other might help to develop novel vaccination strategies and therapeutic approaches.     

Vaccination of mice with recombinant baculovirus expressing spike or nucleocapsid protein of SARS-like coronavirus generates humoral and cellular immune responses

Continuous efforts have been made to develop a prophylactic vaccine against severe acute respiratory syndrome coronavirus (SARS-CoV). In this study, two recombinant baculoviruses, vAc-N and vAc-S, were constructed, which contained the mammalian-cell activate promoter element, human elongation factor 1alpha-subunit (EF-1alpha), the human cytomegalovirus (CMV) immediate-early promoter, and the nucleocapsid (N) or spike (S) gene of bat SARS-like CoV (SL-CoV) under the control of the CMV promoter. Mice were subcutaneously and intraperitoneally injected with recombinant baculovirus, and both humoral and cellular immune responses were induced in the vaccinated groups. The secretion level of IFN-gamma was much higher than that of IL-4 in vAc-N or vAc-S immunized groups, suggesting a strong Th1 bias towards cellular immune responses. Additionally, a marked increase of CD4 T cell immune responses and high levels of anti-SARS-CoV humoral responses were also detected in the vAc-N or vAc-S immunized groups. In contrast, there were significantly weaker cellular immune responses, as well as less antibody production than in the control groups. Our data demonstrates that the recombinant baculovirus can serve as an effective vaccine strategy. In addition, because effective SARS vaccines should act to not only prevent the reemergence of SARS-CoV, but also to provide cross-protection against SL-CoV, findings in this study may have implications for developing such cross-protective vaccines.     

In vitro cellular immune responses to recombinant antigens of Mycobacterium avium subsp. paratuberculosis

Five recombinant antigens (Ags; 85A, 85B, 85C, superoxide dismutase [SOD], and 35-kDa protein) were purified from Mycobacterium avium subsp. paratuberculosis and evaluated for their ability to stimulate peripheral blood mononuclear cells (PMBCs) from fecal-culture-positive cows (low and medium shedders) and culture-negative healthy cows. Recombinant Ags 85A, 85B, and 85C induced significant lymphocyte proliferation as well as the production of gamma interferon (IFN-gamma), interleukin-2 (IL-2), IL-12, and tumor necrosis factor alpha (TNF-alpha), but not IL-4, from low and medium shedders. The 85 antigen complex did not stimulate PMBC proliferation from culture-negative healthy cows. The 35-kDa protein also induced significant lymphocyte proliferation as well as the production of IFN-gamma and IL-4 from low and medium shedders. CD4(+) T cells and CD25(+) (IL-2R) T cells were stimulated the most by 85A and 85B, while the 35-kDa protein primarily stimulated CD21(+) B cells involved in humoral immune responses. Interestingly, SOD was less immunostimulatory than other antigens but strongly induced gammadelta(+) T cells, which are thought to be important in the early stages of infection, such as pathogen entry. These data provide important insight into how improved vaccines against mycobacterial infections might be constructed.