Attempts to inhibit the recognition of soluble antigens by T lymphocytes using antibodies specific for the antigen in question have been uniformally unsuccessful, in contrast to the observed specific inhibition of antibody generation by B cells. One exception is the unique situation whereby anti-hapten antisera inhibit the T-cell proliferative responses observed when hapten-specific T lymphocytes or clones are cultured with hapten-derivatized cells or proteins. The inability to inhibit T-cell functions by antigen-specific antibodies has been interpreted in several ways: (1) T cells possess a different repertoire from B cells; (2) the antibodies tested recognize epitopes present on the native antigen, whereas T cells recognize non-native (processed) structures; (3) the antigenic determinant(s) recognized by T cells on the surface of antigen presenting cells are either not accessible to antibodies, or are present in low amounts. The development of antigen-specific T-cell clones and monoclonal antibodies both specific for the same antigenic determinants now allows this question to be investigated definitively. Here, we report for the first time the specific inhibition of antigen-induced T-cell clone proliferation by a monoclonal antibody directed against the relevant soluble protein antigen.

Animals↗

PubMedDate not supplied

Functional analysis of the murine T lymphocyte immune response to a protozoan parasite, Leishmania tropica.

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Animals↗

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Detection of antibodies to Plasmodium falciparum sporozoites by employing synthetic peptides.

A new achievement in the immunodiagnosis of malaria has been reached after the knowledge of the molecular structure of some plasmodial antigens has become available. One example is given by the repetitive immunodominant epitope of Plasmodium falciparum circumsporozoite protein, which consists of 4 tandemly repeated aminoacids (Asn-Ala-Asn-Pro = NANP). A large synthetic peptide reproducing 40 NANP repeats, (NANP)40, has been shown to reproduce efficiently the native antigen in the CS protein and has been used to develop an enzyme-linked immunosorbent assay (ELISA) for the detection of antisporozoite antibodies in individuals from malaria-endemic countries. This (NANP)40 ELISA has been employed in a longitudinal study in a rural community in Tanzania. The results obtained have shown (i) that the presence of anti-(NANP) antibodies is associated with a certain degree of protective immunity; and (ii) that genetic factors could play a role in the host immune responsiveness to (NANP). Such an ELISA can be easily applied to field research and can be useful for monitoring the immune status of populations participating, in the future, to malaria vaccination trials employing P. falciparum sporozoite peptides.

Adolescent↗