COMPARATIVE ANTIBODY-RESPONSE IN HARBOR AND GREY SEALS NATURALLY INFECTED BY A MORBILLIVIRUS

The antibody response of free-ranging harbour and grey seals, naturall y infected by a morbillivirus, was assessed using a virus neutralizing test and a radio-immunoprecipitation assay. The prevalence of antibod y was similar between species, however, grey seals had significantly h igher virus neutralizing titers. Serum from clinically healthy grey se als precipitated the nucleo-capsid (N) protein along with the hemagglu tinin (H) and fusion (F) glycoproteins. By contrast, significantly few er harbour seal sera precipitated the envelope glycoproteins and respo nses were weaker than those of grey seals. One harbour seal with acute morbillivirus pneumonia, and two with encephalitis precipitated only the N protein. Serum from four harbour seals with encephalitis weakly recognized the envelope glycoproteins, Thus, the antibody response of grey seals appears more competent than that of harbour seals with resp ect to morbillivirus antigens, We speculate that this difference betwe en the species may be an important determinant of morbillivirus suscep tibility.