Prothymosin-α (ProTα) and thymosin-β4 (Tβ4) were isolated from murine thymus and characterized by microsequence analysis. Murine Tβ4 has an identical sequence to bovine Tβ4, whereas murine ProTα is highly homologous to rat ProTα. Murine ProTα differs from rat ProTα at two positions, Glu100 and Asp108 of the rat sequence are substituted by aspartic and glutamic acid, respectively, in murine ProTα. The amount of ProTα in murine thymus was found to be reduced after in vivo treatment with staphylococcal enterotoxin-B (SEB), a superantigen which stimulates T cells bearing specific Vβ receptors. Results from the anti-SRBC (sheep erythrocyte) plaque-forming cell assay showed that the antibody response of the spleen cells from these animals was also suppressed. On the other hand, the amount of Tβ4 was not changed significantly. Our studies suggest that the suppression of SEB on antibody response correlates with the depression of ProTα production in the thymus.
All Science Journal Classification (ASJC) codes
- Structural Biology
- Molecular Biology
- Cell Biology