Antitumor immunity in strain 2 guinea pigs immunized with potassium chloride extracts of L2C tumor cells.

Extracts of L2C tumor cells stimulated in vitro production of macrophage migration inhibitory factor (MIF) in peritoneal exudate cells from guinea pigs immunized with L2C tumor cells. Guinea pigs immunized with extracts of L2C tumor cells that were active in vitro (in the MIF assay) were completely resistant to challenge with viable tumor cells given 2 weeks later. Furthermore, guinea pigs immunized with extracts of L2C tumor cells within 1 hour after challenge with viable L2C tumor cells survived substantially longer than did nonimmunized controls. The immunoprotective and immunotherapeutic effects seen in guinea pigs given injections of viable L2C tumor cells were obtained with extracts of L2C tumor cells but not with extracts of another guinea pig tumor (line 10 hepatoma) or with extracts of normal guinea pig lymphoid cells.

Synchronous regulation of VH and CH allotypes among Ig molecules in multi-heterozygous rabbits suppressed with anti-VH allotype antibody: emergence of IgA from suppression prior to IgG and IgM.

Heterozygous rabbits of genotype a1n81f73g74/a2n82f71g75 were suppressed at birth for the VH region a1 allotype. At 8 weeks of age, quantitative analysis of serum IgG, IgM, and IgA molecules showed that the VHa1 specificity was effectively suppressed in the three classes of Ig and that the suppression was extended to the CH region n81 specificity on mu-chains as well as to the CH region f73 and g74 specificities on alphaf and alphag chains. At 26 weeks of age, analysis of serum IgG and IgM molecules showed that a1 was still suppressed to approximately the same extent in both Ig classes and the suppression was still extended to the CH region n81 specificity. However, at 26 weeks, the percentage of molecules with a1 specificity had doubled among serum and colostral IgA molecules and this increase was extended to the CH region f73 and g74 specificities. Thus, the suppressed allotypes reappeared first among IgA molecules. Our data are consistent with a regulatory mechanism which controls and synchronizes the expression of the VHa and the CH allotypes expressed on the same heavy chain. The order of the re-expression of the suppressed allotypes with respect to Ig class may allow further definition of selective regulatory mechanisms for the synthesis of Ig classes.