The thymus gland: experimental and clinical studies of its role in the development and expression of immune functions

Host response to vaccination

The desired response to vaccination is protection from clinical disease. This article presents several factors, related to both the host and the vaccine, which may result in inadequate protection from clinical disease following vaccination. Also presented is an overview of adverse reactions to vaccines and the response of young animals and pregnant animals to vaccination.

Thymic peptide hormones: basic properties and clinical applications in cancer

The manuscript will provide an in-depth and critical review of the nomenclature, biochemistry, biological properties, and a summary of published and on-going clinical trials with all reported thymic preparations, including both partially purified thymic factors (e.g., thymosin fraction 5, thymostimulin) as well as purified and synthesized thymic peptides (e.g., thymosin alpha 1, thymulin). Particular emphasis will be placed on which thymic peptides should be categorized as true hormones. In addition, the comparative biochemistry and biological activity in animals will be summarized and contrasted for all the currently available thymic factors. The effects, in vitro of thymic factors, on peripheral blood lymphocytes isolated from normal donors and patients with primary immunodeficiency disorders, autoimmune disorders, and neoplastic disorders will also be reviewed. Finally, a detailed critical summary of the clinical trials performed with each of the thymic preparations will be presented with an emphasis on treatment of patients with cancer.

Thymosin-induced reduction of "null cells" in peripheral-blood lymphocytes of patients with systemic lupus erythematosus

Although thymosin, a thymic hormone, has been shown to restore cellular immunity in NZB/NZW mice, its effect in human systemic lupus erythematosus (S.L.E.) and other auto-immune disorders has not been tested. The present study shows for the first time that the proportion of "null cells" in peripheral-blood lymphocytes of patients with active S.L.E. is significantly decreased after in-vitro thymosin treatment. Thymosin has no effect on the percentages of T cells, B cells, and "null" cells in peripheral-blood lymphocytes from normal controls and patients with inactive S.L.E. and active rheumatoid arthritis. These findings suggest that thymosin may play an important part in the pathogenesis and treatment of this condition.

Appearance of T-cell markers in bone marrow rosette-forming cells after incubation with thymosin, a thymic hormone

After incubation with thymosin, a thymic hormone, normal bone marrow rosette-forming cells acquire T-cell characteristics, including increased sensitivity to azathioprine, anti-lymphocyte serum, and anti-theta serum. This activity of thymosin provides a new sensitive and reproducible bioassay for thymosin, and is well correlated with an in vivo graft-versus-host assay. In addition, incubation of spleen cells from adult thymectomized mice with thymosin in vitro restores to normal their diminished sensitivity to azathioprine and anti-lymphocte serum.