Assuntos
Doença Granulomatosa Crônica/complicações , Doença Granulomatosa Crônica/genética , NADPH Oxidases/genética , Tuberculose Pulmonar/imunologia , Adulto , Antituberculosos/uso terapêutico , Biópsia , Brasil , Feminino , Humanos , Mutação , Fagócitos/enzimologia , Fagócitos/patologia , Tuberculose Pulmonar/tratamento farmacológico , Tuberculose Pulmonar/patologia , Adulto JovemRESUMO
Polyclonal B-cell activation is a feature of the early spleen cell response to blood-stage Plasmodium chabaudi malaria. Immunity to blood-stage malaria is guaranteed by the generation of B cells able to produce parasite-specific antibodies mainly from the immunoglobulin (Ig)G2a isotype. In the present study, we characterized the spleen B-cell compartment during blood-stage P. chabaudi infection. The numbers of B220(+) and B220(LOW) CD138(+) (plasma) cells increased sharply between days 4 and 7 post-infection (p.i.). At this time B220(+) cells expressed surface (s)IgM, but nearly all B220(LOW) CD138(+) cells showed concomitantly intracellular (i)IgM and IgG2a. Both follicular and marginal zone B cells were activated expressing high amounts of CD69. At day 40 p.i., B220(LOW) CD138(+) cell population was still increased but, differently from acute infection, 61.1% of these cells were positive for iIgG2a while only 14.2% expressed iIgM. Moreover, at days 20 and 40 p.i., 29.2% and 13.0% of B220(+) cells expressed sIgG2a, respectively. According to cell size and expression of CD80, CD86, CD11b, CD44 and CD38, B220(+) sIgG2a(+) cells had a phenotype characteristic of activated/memory B cells. Furthermore, 14.1% of B220(+) sIgG2a(+) cells at day 30 p.i. expressed a marginal zone B-cell phenotype. Importantly, B cells from 40-day-infected mice were very efficient in presenting parasite antigens leading to proliferation of both CD4(+) and CD8(+) cells. Our results contribute for understanding the dynamics of B cells during P. chabaudi infection, underlying the mechanisms of antigen presentation and antibody production, which are essential for the acquisition of protective immunity against malaria.
Assuntos
Subpopulações de Linfócitos B/imunologia , Malária/imunologia , Malária/parasitologia , Plasmodium chabaudi/imunologia , Baço/imunologia , Animais , Anticorpos Antiprotozoários/biossíntese , Apresentação de Antígeno/imunologia , Subpopulações de Linfócitos B/parasitologia , Subpopulações de Linfócitos B/patologia , Células Cultivadas , Feminino , Imunofenotipagem , Contagem de Linfócitos , Malária/sangue , Camundongos , Camundongos Endogâmicos C57BL , Parasitemia/imunologia , Parasitemia/parasitologia , Parasitemia/patologia , Plasmócitos/imunologia , Plasmócitos/parasitologia , Plasmócitos/patologia , Plasmodium chabaudi/crescimento & desenvolvimento , Baço/citologia , Baço/patologiaRESUMO
Infection by Plasmodium chabaudi results in polyclonal activation, massive proliferation and differentiation of lymphocytes with parasite-unrelated specificities. To verify if polyclonal activation includes experienced B and T lymphocytes and if it modifies pre-established cytokine and Ig-isotype patterns, mice were immunized with ovalbumin (OVA) in alum, a condition that favours T helper 2/immunoglobulin G1 (Th2/IgG1) responses, and infected with P. chabaudi 7 or 80 days later. Polyclonal activation markedly increased the number of anti-OVA Ig-secreting cells in the spleen, an effect more patent in mice infected 7 days after OVA immunization, but also evident in mice infected after 80 days. The Ig-isotype profile predefined by immunization was not qualitatively modified by polyclonal activation. Thus, although P. chabaudi infection preferentially induces IgG2a, the expanded anti-OVA response is dominated by IgG1. Polyclonal expansion of the anti-OVA response did not yield an enlarged memory B-cell pool that could be recalled months later by OVA boosting. Moreover, polyclonal activation of anti-OVA IgG1-secreting cells did not increase this antibody in serum, a probable consequence of the high Ig turnover observed during infection. When OVA-specific T-cell cytokines were evaluated, we observed an increase of both interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) in mice infected 7 days after immunization, whereas in those infected after 80 days, only IL-4 was augmented. These results suggest that polyclonal activation expands experienced B- and T-cell compartments, preserving their antibody and cytokine patterns.
Assuntos
Subpopulações de Linfócitos B/imunologia , Ativação Linfocitária , Ovalbumina/imunologia , Plasmodium chabaudi/imunologia , Subpopulações de Linfócitos T/imunologia , Animais , Anticorpos Antiprotozoários/biossíntese , Anticorpos Antiprotozoários/sangue , Anticorpos Antiprotozoários/imunologia , Células Clonais/imunologia , Feminino , Imunização , Imunização Secundária , Imunoglobulina G/biossíntese , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Isotipos de Imunoglobulinas/biossíntese , Isotipos de Imunoglobulinas/sangue , Isotipos de Imunoglobulinas/imunologia , Memória Imunológica , Interferon gama/metabolismo , Interleucina-4/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Fatores de TempoRESUMO
The mechanisms by which antibodies interfere with Plasmodium growth are still under debate. Characterizing the asexual erythrocyte stages susceptible to antibodies from hyperimmune individuals is therefore a relevant contribution to vaccine research. In this study, using a virulent and synchronous murine malaria parasite, Plasmodium chabaudi chabaudi AJ, we have shown that trophozoites and circulating schizonts are not the main targets for antibodies from hyperimmune serum. In drug-cured mice challenged with a high inoculum of ring-infected erythrocytes, parasitemias do not decline until the moment of erythrocyte rupture, suggesting that effector mechanisms operate immediately prior to reinvasion. Confirming these findings, treatment of primary-infected mice with hyperimmune serum inhibited the generation of new ring forms, but did not alter the numbers of schizont-infected erythrocytes, despite the fact that these cells were recognized by immunoglobulin (Ig)G antibodies. When these mice were treated with IgG1 or IgG2a purified from hyperimmune serum, both subclasses limited reinvasion, but IgG2a showed a stronger protective activity. The fact that Fc digestion decreases but does not abrogate protection suggests that both Fc-dependent and independent mechanisms participate in this process. Treatment with cobra venom factor did not interfere with the antibody-mediated protection, ruling out the participation of the complement system in both lysis and phagocytosis of merozoites or infected erythrocytes. Therefore, in mice suffering from P. c. chabaudi AJ malaria, merozoite neutralization seems to be a major mechanism of protection conferred by hyperimmune serum antibodies. However, FcgammaR-mediated interactions, or other mechanisms not yet defined, may also contribute to inhibit erythrocyte reinvasion.
Assuntos
Anticorpos Antiprotozoários/imunologia , Eritrócitos/parasitologia , Soros Imunes/imunologia , Fragmentos Fab das Imunoglobulinas/imunologia , Imunoglobulina G/imunologia , Malária/imunologia , Plasmodium chabaudi/imunologia , Animais , Modelos Animais de Doenças , Relação Dose-Resposta Imunológica , Feminino , Imunização Passiva , Fragmentos Fab das Imunoglobulinas/uso terapêutico , Imunoglobulina G/uso terapêutico , Estágios do Ciclo de Vida/imunologia , Malária/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Parasitemia/imunologia , Plasmodium chabaudi/crescimento & desenvolvimento , Fatores de TempoRESUMO
The present study shows that CD8+ T lymphocytes expressing low levels of T-cell receptor (TCR)alphabeta, CD8 and CD3 accumulate in the spleen, blood, peritoneum and liver, but not in the lymph nodes of mice chronically infected with Trypanosoma cruzi. Analysis of spleen lymphocytes reveals that most CD8LOW TCRLOW T cells have an experienced phenotype (CD44HIGH CD62LLOW and CD45RA,B,CLOW). These cells have small size, lack activation markers such as CD69, CD25 and CD11b (Mac-1), and do not spontaneously secrete cytokines, suggesting they are at the resting state. When stimulated in vitro with T. cruzi-infected macrophages, TCRLOW CD8LOW T cells behave as parasite-specific memory cells, readily responding with interferon-gamma (IFN-gamma) production. Indeed, among parasite-activated CD8+ lymphocytes, IFN-gamma production was mostly due to TCRLOW CD8LOW cells. Upon in vitro stimulation with anti-CD3/CD28 monoclonal antibodies, down-regulated cells produce IFN-gamma and tumour necrosis factor-alpha, but not interleukin IL-10 or IL-4. Our results indicate that despite parasite persistence, most T. cruzi-specific experienced CD8+ cells are resting. Nevertheless, when encountering infected macrophages these cells differentiate to Tc1 effectors.
Assuntos
Antígenos CD8/metabolismo , Linfócitos T CD8-Positivos/imunologia , Doença de Chagas/imunologia , Regulação para Baixo/imunologia , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Animais , Líquido Ascítico/imunologia , Doença Crônica , Citocinas/biossíntese , Feminino , Memória Imunológica/imunologia , Fígado/imunologia , Linfonodos/imunologia , Ativação Linfocitária/imunologia , Macrófagos/imunologia , Camundongos , Camundongos Endogâmicos A , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Baço/imunologiaAssuntos
Antígenos de Protozoários/metabolismo , Glicoproteínas/metabolismo , Malária/parasitologia , Plasmodium chabaudi/metabolismo , Proteínas de Protozoários/metabolismo , Animais , Anticorpos Monoclonais/imunologia , Antígenos de Protozoários/biossíntese , Antígenos de Protozoários/imunologia , Eritrócitos/parasitologia , Técnica Indireta de Fluorescência para Anticorpo , Glicoproteínas/biossíntese , Glicoproteínas/imunologia , Proteína 1 de Superfície de Merozoito/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Peso Molecular , Plasmodium chabaudi/crescimento & desenvolvimento , Plasmodium chabaudi/imunologia , Proteínas de Protozoários/biossíntese , Proteínas de Protozoários/imunologia , SolubilidadeRESUMO
To obtain low and high parasite loads in the acute phase of Chagas' disease, A/J mice were infected with 10(3) or 10(5) Trypanosoma cruzi trypomastigotes of the Y strain and treated on day 6 with benznidazol. One year later, chronically infected mice were screened for subpatent parasitemias, tissue pathology, and immune response. Mice infected with the high parasite inoculum showed higher levels of chronic parasitemias, heart and striated muscle inflammation, and activation of the immune system than did mice infected with the low inoculum. Concerning the activation of the immune system, the main findings for high-dose-infected mice were (i) increased numbers of splenocytes, with preferential expansion of CD8(+) and B220(-) CD5(-) cells, many of them bearing a macrophage phenotype; (ii) higher frequencies of B (B220(+)), CD4(+), and CD8(+) large lymphocytes; (iii) a shift of CD4(+) cells towards a CD45RBLow phenotype; (iv) increased frequencies of both CD45RBLow and CD45RBHigh large CD4(+) cells; (v) augmented numbers of total immunoglobulin (Ig)-secreting cells, with predominance of IgG2a-producing cells; and (vi) increased production of gamma interferon and interleukin 4. In addition, these mice presented lower IgM and higher IgG2a and IgG1 parasite-specific serum antibody levels. Our results indicate that the parasite load at the acute phase of T. cruzi infection influences the activation of the immune system and development of Chagas' disease pathology at the late chronic phase of the disease.
Assuntos
Doença de Chagas/imunologia , Doença de Chagas/patologia , Sistema Imunitário/parasitologia , Parasitemia/imunologia , Parasitemia/patologia , Trypanosoma cruzi/imunologia , Doença Aguda , Animais , Anticorpos Antiprotozoários/sangue , Células Produtoras de Anticorpos/patologia , Linfócitos T CD4-Positivos/metabolismo , Doença de Chagas/parasitologia , Doença Crônica , Citocinas/metabolismo , Feminino , Sistema Imunitário/patologia , Injeções Intraperitoneais , Antígenos Comuns de Leucócito/biossíntese , Subpopulações de Linfócitos/imunologia , Subpopulações de Linfócitos/patologia , Camundongos , Camundongos Endogâmicos A , Músculo Esquelético/parasitologia , Músculo Esquelético/patologia , Miocardite/parasitologia , Miocardite/patologia , Miosite/parasitologia , Miosite/patologia , Parasitemia/parasitologia , Baço/imunologia , Baço/metabolismo , Baço/patologiaRESUMO
T. cruzi-infected macrophages are potential candidates for the presentation of parasite antigens to T. cruzi-specific T lymphocytes. To assess this question, we examine the ability of peritoneal exudate macrophages to process exogenous live or dead parasites and to activate defined populations of T. cruzi-specific immune T-cells. Macrophages infected with live amastigotes activated both lymph node CD4+ and spleen CD8 + T-primed cells that proliferated and secreted cytokines. Lymph node CD4+ T-cells produced IFN-gamma and IL-10 while CD8 + T-cells produced IFN-gamma. In contrast, macrophages pulsed with dead parasites activated only lymph node CD4+ T-cells, which proliferated and secreted IFN-gamma. Interestingly, the immunization with heat-killed parasites primed mice for CD8+ T-cells which were expanded in vitro by recognition of infected macrophages. Taken together, these results demonstrated that amastigote infected macrophages present parasite peptides associated with MHC I and II molecules, activating both CD4 + and CD8+ T-cells. Furthermore, the development of T. cruzi-specific CD8+ T-cells in vivo using the immunization protocol with non-living parasites as described in this report could be explored for further studies on the role of CTL in the outcome of infection.
Assuntos
Antígenos de Protozoários/imunologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Comunicação Celular/fisiologia , Ativação Linfocitária/imunologia , Macrófagos Peritoneais/imunologia , Macrófagos Peritoneais/parasitologia , Trypanosoma cruzi/imunologia , Animais , Anticorpos Monoclonais/farmacologia , Apresentação de Antígeno/imunologia , Células Apresentadoras de Antígenos/imunologia , Células Apresentadoras de Antígenos/parasitologia , Antígenos CD4/imunologia , Linfócitos T CD4-Positivos/metabolismo , Antígenos CD8/imunologia , Linfócitos T CD8-Positivos/metabolismo , Interferon gama/biossíntese , Interleucinas/biossíntese , Linfonodos/citologia , Linfonodos/imunologia , Linfonodos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Fenótipo , Sensibilidade e Especificidade , Baço/citologia , Baço/imunologia , Baço/metabolismoRESUMO
In this work, the authors analysed T and B lymphocyte subsets and cytokine production in the spleen of BALB/c mice during polyclonal lymphocyte activation (primary infection) and parasite-specific response to Plasmodium chabaudi chabaudi (secondary infection). The secondary response was evaluated in fully immunoprotected animals, 60 days after a chloroquine-cured infection. The authors observed that in polyclonal lymphocyte activation antibody-secreting cells of all isotypes increased, with predominance of IgG2a and IgG3 classes. At that time, IFN-gamma was largely produced, but IL-4/IL-5 were just slightly enhanced. In mice re-infected after 60 days, the Ig-isotype pattern was restricted to IgG1 and only IL-4/IL-5 were produced. In both responses, however, the levels of IL-2 were greatly reduced, while those of IL-10 were enhanced to similar levels. The different involvement of Th1 and Th2 cells in both responses was confirmed through analysis of CD45RB expression by CD4+ cells. The authors observed that CD45RBhigh cells were the major CD4+ subpopulation in primary infected mice, while CD45RBlow cells predominated in 60 days re-infected animals. Moreover, the great majority of activated (large) CD4+ cells in the primary infection belonged to the CD45RBhigh subset, while after reinfection most of the CD4+ large had a CD45RBlow phenotype.
Assuntos
Anticorpos Antiprotozoários/biossíntese , Linfócitos B/imunologia , Linfócitos T CD4-Positivos/imunologia , Isotipos de Imunoglobulinas/biossíntese , Memória Imunológica , Interferon gama/biossíntese , Interleucina-4/biossíntese , Antígenos Comuns de Leucócito/metabolismo , Plasmodium chabaudi/imunologia , Animais , Células Produtoras de Anticorpos/metabolismo , Linfócitos B/metabolismo , Linfócitos T CD4-Positivos/metabolismo , Linfócitos T CD8-Positivos/imunologia , Feminino , Cinética , Malária/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Especificidade da EspécieRESUMO
Adult BALB/c male mice were injected with a single dose of ethyl nitroso urea (ENU; 250 mg/Kg, ip) and mated to C57BL/6, DBA/2 AND A/J adult females 13 weeks later. F1 males were mated with BALB/c females and F2 females were then backcrossed to the F1 parents. One BALB/c male mouse thus teated gave origin to a mutant presenting hair and skin alterations similar to those of natural hairless mutants. The new mutation is located on chromosome 14 near the Es10 locus, and probably at the same locus for the hairless mutation. Similar to the hairless mouse, this new mutant has a normal phenotype at birth and after three weeks starts to loose hair which is never replaced. Additionally, the skin becomes thickened and wrinkled. One feature that distinguishes this mutant from other hairless mice is the peculiar enlargement of its axillary and cervical lymph nodes. The new mutant develops membranoproliferative glomerulonephritis similar to the rhino mouse, one of the hariless allele mutants already described in the literature, but with a much later onset