Interference with the uptake of guinea-pig agglutinins in mice due to fractions of papain hydrolyzed rabbit γ-globulin

Abstract

Antibodies from immune serum ingested by suckling mice and rats may enter into their circulations. The normal sera of certain species, when mixed with the immune serum administered, reduce the entry of antibodies. This effect was called interference. Interference with the uptake of guinea-pig agglutinins in mice due to rabbit serum and $\gamma $-globulin and to fragments I, II and III of rabbit $\gamma $-globulin, fractionated by the digestion method of Porter, is investigated. The effect of rabbit serum is due mostly, if not wholly, to its $\gamma $-globulin. Interference due to fragments I and II is negligible, whereas interference due to fragment III is at least 3$\cdot $5 times greater than that due to the whole $\gamma $-globulin molecule. It is concluded that most of the configurations of the whole rabbit $\gamma $-globulin molecule which are recognized by mouse cells as heterologous are carried on fragment III. A hypothesis, which postulates a specific receptor within absorptive cells concerned with the transmission of antibodies across the gut of some young rodents, is discussed in the light of these results, when it is suggested that the receptor may be better adapted to receive the species-specific parts of antibody molecules rather than the residual or antibody reactive parts.