beta sub(2)-Microglobulin-Like Molecules in Low Vertebrates and Invertebrates

The occurrence of a beta sub(2)m-microglobulin-( beta sub(2)m) like molecule in the sera and extracts from several low-vertebrates and invertebrates has been studied by using 3 homologous and 8 heterologous radioimmunoassay systems. Eight of the RIA were based on the principle of competition between "cold" and radiolabeled beta sub(2)m whereas 3 other RIA examined the capacity of the unknown reagents to impede the binding of beta sub(2)m to guinea pig or cod spleen cells or to compete with beta sub(2)m in its interaction with purified AgB antigens. beta sub(2)m-like molecules were detected in the serum and extracts of the lizard (Anolis carolinesis)) and the goldfish (Carassius auratus ) but no evidence was found for the presence of such molecules in the extracts made from the newt (Triturus viridescens ). The preparations made from the salamander (Necturus maculatus ), the African clawed frog (Xenopus laevis ), the catfish (Ictalurus punctatus ), and the hydra (Hydra littoralis ) were positive for beta sub(2)m only in 10 to 29% of the assay systems. The extracts made from 2 invertebrate species; the earthworm (Lumbricus terrestris)) and the crayfish (Cambarus diogenes ) proved to be strongly positive for beta sub(2)m by all assays and criteria. The sera from several crayfish and lobsters (Homarus americanus)) and the extracts from these lobsters showed significant variability in beta sub(2)m-like activity, the lobsters sera being the most positive (27% of the assays).