Antigenicity of insulin: diabetes induced by specific antibodies

Publisher Website
Google Scholar
Abstract
Intravenous injection of pig or ox or sheep insulin, caused anaphylactic shock in guinea pigs sensitized with crystalline pig or ox insulin. Neutralizing antibodies for insulin were induced in guinea pigs and in sheep by injections of insulin in Freund''s adjuvant. Animals producing antibodies were resistant to insulin. Serum from these animals neutralized insulin, as shown by inoculation into normal mice. This neutralization took place whether the insulin and serum were mixed together before injection or were injected separately at different times. Endogenous guinea pig and sheep insulins were not neutralized by homologous antibodies. Two types of guinea pig insulin were prepared which were immunologically distinct. One type, classed as altered, was neutralized by immune guinea pig serum. The other, like endogenous guinea pig insulin, was not neutralized. The sheep insulins tested, which included one commercial preparation, were neutralized by immune sheep serum and therefore may be classed as altered. This study indicates that endogenous guinea pig insulin is immunologically distinct from altered guinea pig insulin, from endogenous mouse insulin, and from preparations of pig, ox, sheep and rabbit insulin; and that endogenous sheep insulin is immunologically distinct from altered guinea pig insulin and from preparations of pig, ox, sheep and rabbit insulin. Mice were rendered diabetic by injection of guinea pig anti-insulin serum. These diabetic mice showed abnormally high blood-glucose levels, loss of weight, and acetone bodies in the urine during the period of administration of serum.