BIOLOGY OF SPERMATOZOA 



773 



ing its origin or possible role, if any, during 

 normal reproductive processes. 



The effects of antiserum on the gametes 

 have been discussed in a previous section. 

 It will be recalled that the tyi)ical cell- 

 specific agglutination and inniiobilization 

 responses can render the sperm incapable of 

 fertilization. Further, the experiments of 

 Kiddy, Stone and Casida (1959) suggest a 

 differential effect of treatment with high and 

 low concentrations of antisperm serum. The 

 former impairs fertilizing capacity; the 

 latter results in abnormal development after 

 fertilization (see section on Lnmunologic 

 Problems) . 



The impendency of fertilization provokes 

 consideration of several types of sperm re- 

 sponses which can profitably be introduced 

 here and further elaborated on in the chap- 



ter by Blandau. These responses involve 

 interrreactions of the sperm and egg, or egg 

 exudates, and concern such processes as 

 chemotaxis, sperm activation, sperm agglu- 

 tination, and the acrosome reaction. 



With respect to the occurrence of chemo- 

 taxis, that is, the directed movement toward 

 the egg in response to a chemical gradient 

 from the egg, the evidence relating to ani- 

 mal gametes is essentially negative (Roths- 

 child, 1956b). Many earlier claims for 

 sperm chemotaxis among lower animals (see 

 Hcilbrunn, 1943), and certain recent reports 

 on mammalian species (Hiibner, 1955; 

 Schuster, 1955; Schwartz, Brooks and Zins- 

 ser, 1958), can be readily ascribed to "trap- 

 action," that is, the accumulation of sperm 

 in the vicinity of the egg or egg substance, 

 and not to a nonrandom movement of the 



k 



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?^B 





'♦ 



W^ 



Fig. 13.19. Fertilizin reaction in nianinial. Agglutination of rabbit .sperm in immediate 

 vicinity of egg collected from rabbit oviduct. Sperm agglutinates form predominantly in 

 head-to-head patterns. (From D. W. Bishop and A. Tvler, J. Exper. Zool., 132, 575-601, 

 1956.) 



