Enhancement of autologous tumor vaccine immunogenicity by anti-Gal

Natural anti-carbohydrate IgM in mice: dependence on age and strain

Natural anti-carbohydrate antibodies in humans play a key role in natural immunity and in recognition of allogeneic and xenogeneic antigens. Presumably, natural anti-carbohydrate antibodies in mice have similar functions; but these antibodies have not been extensively characterized. An assay was developed and used to screen for anti-carbohydrate IgM in the serum of BDF-1 mice. Among the natural anti-carbohydrate IgM identified, anti-betaGlcNAc IgM were the most abundant. Anti-betaGlcNAc IgG was not detected. Levels of anti-betaGlcNAc IgM were very low in 3-week-old BDF-1 mice and increased until 5 to 7 months of age. Levels of serum anti-betaGlcNAc IgM similar to those in BDF-1 mice were found in the serum of some strains related to the BDF-1 strain (DBA and C57BL/6) and in BDF mice lacking the galactosyl transferase gene. However, in two strains unrelated to the BDF-1 strain (FVB and SJL), levels of anti-betaGlcNAc IgM were less than one-tenth of those found in BDF-1 mice. These results provide considerable insight into the effect of age on the production of natural anti-carbohydrate antibodies in mice and indicate that production of those antibodies is strongly dependent on the strain of mouse. These studies will help in future development of murine models for studying the biological and medical roles of natural anti-carbohydrate antibodies.

Exposure to topical bovine thrombin during surgery elicits a response against the xenogeneic carbohydrate galactose alpha1-3galactose

Exposure of humans to topical bovine thrombin has been associated with development of antibodies against bovine and human coagulation factors and blood coagulation abnormalities. However, the nature of this humoral response is unknown. In this study, numerous glycoproteins in the topical bovine thrombin were found to contain the Gal(alpha1)-3Gal epitope, which is known to be highly immunogenic. More importantly, Gal(alpha1)-3Gal is recognized by natural antibodies that are found in all normal individuals and are known to effectively mediate complement activation and subsequent destruction of xenogeneic tissues. Thus, primary exposure of normal individuals to topical bovine thrombin is expected to result in an immediate immune reaction against that reagent. Further, following exposure to topical bovine thrombin, the levels of anti-Gal(alpha1)-3Gal IgG rose to levels tenfold greater than the average level of natural anti-Gal(alpha1)-3Gal IgG in naive individuals. Thus, Gal(alpha1)-3Gal in topical bovine thrombin accounts for, at least in part, the highly immunogenic nature of this reagent.