IMMUNOGLOBULIN IN THE EGGS OF THE CHANNEL CATFISH (ICTALURUS-PUNCTATUS)

Egg yolk proteins obtained from 2-3-day-old fertilized channel catfish eggs were analyzed to determine if immunoglobulin (Ig) was present. U sing both monoclonal and polyclonal antibodies to catfish Ig, egg Ig w as isolated and structurally characterized. The egg Ig when analyzed i n SDS-gels under nonreducing conditions dissociated into eight distinc t subpopulations with relative mobilities identical to that previously described for the serum Ig of the channel catfish. In addition, the c omponent heavy (H) and light (L) chains of the egg Ig had similar rela tive mobilities as the H and L chains identified in serum Ig. Immunocy tological studies using both polyclonal and monoclonal anti-catfish Ig showed that Ig was dispersed throughout the yolk of the egg. In addit ion these analyses indicated that Ig was localized within the external membranes (eggshell) of the egg.