Specific immune response enhancing factor in serum of immunised mice

Antigen-specific helper activity in serum of mice primed with sheep red cells II. Partial purification of the factors involved

The nature of antigen-specific, T-cell dependent helper activity (SSHA), present in serum of mice 9 h after intraperitoneal immunization with 2 x 10(8) sheep erythrocytes, was studied in more detail. SSHA could be enriched from serum by adsorption to formalinized sheep erythrocytes, elution of the cells with a chaotropic substance, and subsequent dialysis. This resulted in an enrichment of about 900 x with a yield of 64%. Further fractionation of the material by ultrafiltration resulted in two subfractions with helper activity indicating SSHA to be composed of two factors with mol. wt's of greater than 300,000 and about 60,000. The eventual purification for the two factors was about 1650 and 2000 x respectively, and the total yield 46%. The possible relationship between the factors and factors described by others after induction in vitro is discussed. The purification procedure appears useful for the enrichment of SRBC-specific helper factors from serum.

Antigen-specific T-cell factors

Antigen-specific T-cell factors are mediator molecules which are produced by helper and suppressor T cells and which can perform the function of those cells in an antigen-specific manner. They probably play an important part in immunoregulation. The major histocompatibility complex has a controlling influence on their structure and activity, while their antigen-recognition properties may be conferred by immunoglobulin V regions. Interest in the factors derives from three related areas of research, namely (i) the problem of T-cell recognition of antigen; (ii) the mechanisms of cellular interactions in antibody production and cell-mediated immunity; and (iii) the genetic control of immune responses. This review discusses the literature up to June 1980 on their production, structure, genetic restriction and mechanism of action.