TCR gamma delta cells: mysterious cells of the immune system.

Gamma delta cells participate in pathogenic infections and autoimmune conditions, yet, almost a decade after their discovery, little is known regarding their TCR repertoire or effector functions. Unlike MHC-restricted antigen recognition employed by TCR alpha beta cells, TCR gamma delta cells can recognize whole unprocessed antigens in an MHC- independent manner. The nature of positive and negative selection used to shape the repertoire of TCR gamma delta cells is unclear, especially in the nonlymphoid tissues where these cells predominate.

Synthetic gonadotrophin-releasing hormone (GnRH) vaccines incorporating GnRH and synthetic T-helper epitopes.

A vaccine against the gonadotrophin-releasing hormone (GnRH) is being developed as an immunological method for treatment of prostatic hypertrophy, based on the observation that active immunization against GnRH leads to the production of anti-GnRH antibodies which results in the shrinkage of the prostate gland. We have been investigating the regulation of anti-GnRH antibody responses by carrier molecules. In previous studies we showed that the use of large protein molecules as carriers limits the use of such a vaccine owing to potential problems of carrier-induced anti-haptenic suppression.

Bypass by an alternate 'carrier' of acquired unresponsiveness to hCG upon repeated immunization with tetanus-conjugated vaccine.

We report here the use of an alternative carrier diphtheria toxoid (DT) in human subjects to overcome antigen-specific unresponsiveness upon immunization with a hapten/ligand-carrier conjugate. In the phase I clinical trial of a birth control vaccine using gonadotrophin subunits linked to tetanus toxoid, some of the subjects failed to evoke a booster antibody response to human chorionic gonadotrophin (hCG). Presentation of the ligand on DT instead in subsequent immunizations restored anti-hCG response.