Specificity of in Vitro Murine B Cell Activation by Protein and Polysaccharide Polymers

[摘要] The ability of various polynucleotide and carbohydrate polymers to induce B cell mitogenesis as measured by the uptake of 3H-thymidine was studied. Cell suspensions depleted of T cells were obtained from spleens of Nu/Nu, TxBm mice, or by treatment of normal spleens with anti-θ serum and complement. Specific B cell activation was demonstrated by the use of the following single and double stranded ribopolynucleotides, poly A, U, A·U, G, and X. In addition, carbohydrate polymers, such as dextran sulfate and methylcellulose, as well as the thymic-independent antigens, pneumococcal polysaccharide (SSSIII) and polymerized flagellin (POL), produced B cell activation. Two other B cell antigens, polyvinylpyrrolidone and Ficoll, did not appear to act as mitogens. A highly charged polymer, CM-Ficoll, also failed to stimulate. Although dextran sulfate (m.w. 500,000) produced activation, the lower molecular weight dextran sulfate (m.w. 75,000) did not. LPS contamination of all mitogenic materials was ruled out by the use of an antisera directed against the active portions of LPS, lipid-A. Confirmation of specific B cell activation was obtained by the eliminations of responses by anti-MBLA treatment of cell suspensions and the failure of activated suspensions to produce lymphotoxin, a T cell lymphokine which can be induced with PHA or Con A. These studies indicate that B cell activation requires a unique molecular structure not limited singly by polymeric repeating determinants or a polyanionic nature but also a minimum molecular weight as well as secondary and tertiary characteristics of the mitogenic compound. The characteristics associated with the ability of a molecule to activate specifically B cells is discussed.

[学科分类] 生物科学（综合）