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Mice infected with Schistosoma japonicum were resistant to the intestinal nematode, Strongyloides venezuelensis. The numbers of adult S. venezuelensis recovered from mice were significantly decreased when infections were given from 6 weeks after S. japonicum infection. Larval recovery from the lungs showed that significant numbers of subcutaneously inoculated S. venezuelensis larvae were eliminated by 3 days in S. japonicum-infected mice (P < 0.0001), while histology revealed that this was associated with massive eosinophilic infiltration in the lungs. In addition, adult S. venezuelensis worms implanted in the duodenum of S. japonicum-infected mice could not establish in the intestine. This failure was associated with mucosal mastocytosis. Activation of eosinophils and intestinal mast cells was correlated with elevated expression of mRNA for interleukin (IL)-3, IL-4, and IL-5 in S. japonicum-infected mice. Sera from S. japonicum-infected mice recognized S. venezuelensis larva antigens as strongly as those from S. venezuelensis-infected mice, although transfer of sera from S. japonicum-infected mice to normal recipient mice did not protect them from S. venezuelensis challenge infection. It was concluded that the mechanisms for larval killing and adult worm expulsion of S. venezuelensis in S. japonicum-infected mice were identical to those seen in infections with S. venezuelensis only.

We evaluated the hypothesis that serum IgE regulates neutrophil FcεRI expression in the same manner as described for other FcεRI + cells. FcεRI expression by neutrophils of 40 asthma subjects and 20 control subjects did not correlate with serum IgE levels, whereas FcεRI expression by basophils of the same subjects showed a highly significant correlation. The level of FcεRI expression by neutrophils of both asthma and control subjects was approximately 1% of that for basophil FcεRI expression. IgE + neutrophils were minimally detectable, and FcεRI α subunit was not detected in Western blots of neutrophil membranes and cytosol. The neutrophil FcεRI did not support antiIgE stimulated superoxide release or IgE-induced increase in neutrophil survival. We conclude that FcεRI expression by neutrophils of both asthma patients and control individuals is minimal at best and that, if present, neutrophil FcεRI expression, unlike that of other human FcεRI + cells, is not regulated by serum IgE.

Background: MSP-1 of Plasmodium falciparum induces strong prohferative T cell responses even in malaria-nonexposed individuals. Epitopes recognized by malaria-nonimmune T cells have not been identified, and immunological mechanisms inducing such T cell responses remain to be uncovered. MSP-1 is a vaccine candidate, and it should be understood whether those epitopes have any roles in MSP-1-mediated protective immunity. The T epitopes-inducing malaria-naive T cell response was analyzed in the hope of understanding the underlying mechanisms. Methods: Human T cell lines and clones reactive to MSP-1 of P. falciparum were established from malaria-nonexposed Japanese donors in vitro, and epitope peptides were identified. Sequences of those epitope peptides were compared to unrelated peptides in the data base. One of those peptides was tested for both binding to HLA-DR molecules and inducing prohferative responses of MSP-1-reactive T cells. Results: There are at least 6 epitopes recognized by malaria-naive T cells under the restriction by HLA-DRBΓ1502 or 0802. Important amino acids for the T cell recognition were identified for an MSP-1 pep-tide. A yeast peptide which shared those residues induced prohferative responses of MSP-1-reactive T cells. Conclusion: We identified T epitopes in the N-terminal region of MSP-1, some of which showed molecular similarities with unrelated environmental antigens, suggesting the presence of cross-reactive T epitopes in MSP-1. Cytokine production in response to those epitopes suggests regulatory functions of those T cells during primary infection with P. falciparum.

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Objective HIV-1 bound to intact neutrophils efficiently infects activated peripheral blood mononuclear cells (PBMC). Here, we evaluated the effect of the local milieu created by activated PBMC before and after HIV-1 infection on neutrophil survival and HLA-DR expression, with emphasis placed on a role for GM-CSF. Methods PBMC of healthy adult individuals were activated by phytohemagglutinin (PHA) or anti-CD3/anti-CD28 and were subsequently cultured without (HIV-1−) or with HIV-1 (HIV-1+). The effects of the culture supernatants or recombinant GM-CSF on survival and HLA-DR expression by neutrophils of healthy adult individuals and of HIV-1-infected individuals were evaluated using flow cytometry. Results Conditioned medium from PHA-activated PBMC (HIV-1− and HIV-1+) increased neutrophil survival and induced HLA-DR expression by neutrophils of healthy individuals in a GM-CSF dependent fashion. HIV-1 infection variably, but consistently, increased GM-CSF production by PHA-activated PBMC but not GM-CSF production by anti-CD3/anti-CD28-activated PBMC. The latter was correlated with a loss of CD3+GM-CSF+ cells after infection. Neutrophils of elite controllers exhibited a diminished HLA-DR response to GM-CSF in culture, whereas neutrophils of HIV-1+ subjects having a low viral load on anti-retroviral therapy or subjects with a high viral load exhibited a range of HLA-DR responses. Conclusions GM-CSF production within the mucosa or draining lymph nodes may promote HIV-1 infection by facilitating sustained contact between viable neutrophils with bound HIV-1 and CD4 lymphocytes. The minimal effect of GM-CSF on HLA-DR expression by neutrophils of elite controllers provides indirect support for this conclusion.

Binding capacities of synthetic peptides to HLA‐DR molecules were tested on filter papers to identify putative helper T‐cell epitopes on a malarial protein. The antigen tested was the merozoite surface glycoprotein 1 (MSP1) of Plasmodium falciparum, a vaccine candidate targeting the asexual erythrocytic stage. Bindings between synthetic oligopeptides and HLA‐DR molecules were tested. Such bindings were not non‐specific, and a known helper T‐cell epitope peptide showed positive binding to the restricting HLA‐DR molecule. By using this screening system, we observed the unequal distribution of HLA‐DR‐binding peptides in 10 out of 17 MSP1 blocks tested. Block #6 of MSP1 seemed to show the highest frequency in the positive binding; on the other hand, blocks #1 and #17, both of which were thought to be vaccine candidate regions, contained fewer HLA‐DR binding peptides. This was not inconsistent with the results that block #17 was less stimulatory to peripheral T cells than block #6. The peptides with positive binding to HLA‐DR showed actual epitope activities when we tested peptide‐driven proliferation of human bulk T‐cell lines, and association between the two parameters was statistically significant (P < 0.001). For more detailed information for vaccine development, peptides with both IgG‐ and HLA‐DR binding activities were mapped in block #17 of MSP1. Together with these results, we demonstrate that our simple screening system seems to provide essential information for vaccine development through uncovering locations of putative epitopes for human helper T cells.

ABSTRACT. We aimed to explore the changes of peripheral B1 cells before and after treatment of adult idiopathic thrombocytopenic purpura (ITP) and to investigate the association of these changes with the disease condition and prognosis. Ninety-seven ITP patients were divided into the effective or ineffective groups, based on their response to hormone therapy. Forty healthy volunteers were enrolled into the control group (HC). The percentages of CD19 + cells, B1 cells, and platelet-associated immunoglobulin (PAIg) in peripheral blood from healthy volunteers and ITP patients before and after treatment were evaluated, and blood platelet (PLT) counts were determined. The percentages of CD19 + cells [(21 ± 10.0) vs (11.2 ± 7.1)%], B1 cells [(8.85 ± 5.23) vs (2.2 ± 1.3)%], and PAIg [(28 ± 19) vs (11.7 ± 8)%] in whole blood from ITP patients before treatment were significantly higher than those in whole blood from healthy controls (P < 0.05). Before treatment, the percentage of B1 cells and PAIg in ITP patients was negatively correlated with the PLT level (r = -0.89, P < 0.05 and r = -0.814, P < 0.05, respectively). Further, the B1 cell percentage was positively associated with the PAIg percentage in ITP patients before treatment. In the effective group, the B1 cell percentage was reduced sharply at 1 month after treatment [(2.45 ± 1.75) vs (8.74 ± 5.04)%, P < 0.05)], so as at 3 and 6 months. However, in the ineffective group, there was no difference in the B1 cell percentage before and after treatment [(7.9 ± 5.6) vs (8.76 ± 5.26)%]. This obvious association of changes in peripheral B1 cells with disease condition and prognosis in ITP patients may be of certain clinical significance for guiding the individualized treatment of ITP.