FATE OF MUMPS VIRUS IN THE EMBRYONATED EGG AS DETERMINED BY SPECIFIC STAINING WITH FLUORESCEIN-LABELLED IMMUNE SERUM

Abstract

Specific staining with fluorescein-labeled immune serum was used to study the progress of mumps virus infection in a series of embryos harvested at daily intervals. The results were compared with the hemagglu-tinin and infectivity titers of the corresponding extra-embryonic fluids. The evidence obtained indicated that the multiplication of the virus was restricted to those cells which came into surface contact with infected fluid. Following intra-amniotic inoculation into 8-day-old embryos, these included the cells lining the amniotic membrane and the epidermal and pharyngeal epithelium. Depending apparently on the extent of the contamination of the allantoic cavity and of the extra-embryonic coelom in the course of inoculation, varying amts. of virus were also present in the cells lining the chorio-allantoic membrane and occasionally in the peritoneum. During the later stages of the infection, staining which was principally if not entirely extracellular was seen in the gastro-intestinal tract, and, after the dissolution of the tracheal plug, in the respiratory tract. The staining of the tissues closely paralleled the rise and fall in the infectivity of the extra-embryonic fluids. The development of hemagglutinins, on the other hand, provided a less sensitive measure of virus multiplication than did the staining.