HEMAGGLUTINATION BY ANIMAL VIRUSES 45 



single hemagglutinin, separate from the virus particle. Filtered together, both 

 are retained by a Seitz disc; but filtered in the separate state, the heavier 

 hemagglutinin is retained by the disc, while the lighter hemagglutinin is 

 filterable. The lighter hemagglutinin was destroyed at 56°C. after 45 minutes, 

 and agglutinated red cells at all temperatures from 5 to 37°C. The heavier 

 hemagglutinin survived heating at 70°C, and while it reacted with red cells 

 to lower titer at 5°C, hemagglutinated best at 37°C, as did the combined 

 native hemagglutinin (Clark and Nagler, 1943). 



Previous studies had considered these hemagglutinins as one agent. They 

 had found the titer to vary considerably over a range of fowl red cells, some 

 fowl cells being completely insusceptible (Burnet and Stone, 1946; Burnet 

 and Boake, 1946) and only about 50 % of fowl cells giving a good titer 

 (Clark and Nagler, 1943). The proportion of fowls having easily agglutinable 

 red cells increases with age, from % of embryos or chicks 2 days old to 

 23 % of chicks 14 days old and 55 % of fowls 6 to 30 months old (Clark and 

 Nagler, 1943). Cells from a proportion of pigeons are also agglutinated 

 (Burnet and Stone, 1946) but not cells from man, horse, sheep, rabbit, finch, 

 or canary. Mouse cells are occasionally agglutinated to low titer by vaccinia. 

 Ectromelia (mousepox) agglutinates all mouse cells, and also those fowl cells 

 sensitive to vaccinia. No enzyme has been found associated with vaccinia 

 hemagglutinin, and the red cell receptor for influenza and vaccinia are 

 distinct. 



Vaccinia hemagglutinin is believed to be predominantly phospholipid. It 

 is inactivated in the presence of calcium by the type C lecithinase of CI. 

 welchii a-toxin, and by the type A lecithinase of cobra venom (Stone, 1946a). 

 Those fowl cells sensitive to vaccinia hemagglutinin are also agglutinated by 

 suspensions of tissue lipids (Burnet and Stone, 1946) and suspensions of pure 

 and mixed lipids of the phospholipid group (Stone, 1946b). Whereas vaccinia 

 hemagglutinin is inhibited only by specific antibody, nonspecific lipid agglut- 

 inin is inhibited by normal serum. 



Vaccinia hemagglutinin has been recovered from chorioallantoic membrane 

 where it develops during the production of infective virus (Metcalf, 1955), 

 from rabbit skin, rabbit testis, and sheep lymph (Chu, 1948a). It was not 

 found in calf lymph by Nagler (1942), possibly because of the presence of an 

 inhibitor. 



Two strains of neuro-vaccinia, and two rabbitpox strains, were found by 

 Fenner (1958) to lack any capacity to produce hemagglutinin. 



References 



Ada, G. L., and French, E. L. (1950). Australian J. Sci. 13, 82. 

 Ada, G. L., and French, E. L. (1957). Australian J. Sci. 19, 227. 

 Ada, G. L., and Stone, J. D. (1950). Brit. J. Exptl. Pathol. 31, 263. 



