title: Enhancement of in vitro antibody responses by human serum proteins cleaved by trypsin.
abstract: Tryptic cleavage of human serum proteins remarkably enhanced in vitro plaque-forming cell (PFC) responses of mouse spleen cells primed with sheep erythrocytes (SE). Moreover, trypsin cleaved proteins could mimic the activity of T-cells in immune responses of SE-primed B cells. Eluted with 6 M guanidine-HCl on a Sepharose 6B-CL Column, the activity was found in the fraction corresponding to the molecular weight greater than 100,000. The results suggest that tryptic cleavage of human serum proteins produced a factor(s) that resembled the T-cell augmentation of B-cell immune responses.
mesh_terms: D000818:Animals; D000917:Antibody Formation / Q000187:drug effects*; D001798:Blood Proteins / Q000032:analysis*; D002478:Cells, Cultured; D005260:Female; D006462:Hemolytic Plaque Technique; D006801:Humans; D066298:In Vitro Techniques; D015848:Interleukin-5; D008222:Lymphokines / Q000096:biosynthesis; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D014357:Trypsin / Q000494:pharmacology*
chemical_list: D001798:Blood Proteins; D015848:Interleukin-5; D008222:Lymphokines; D014357:Trypsin