PEOCEEDINGS OF 



THE ROYAL SOCIETY 



Suction B. — Biological Sciences. 



On Opsonins in Relation to Red Blood-cells. 

 By J. 0. Wakelin Barratt, M.D., D.Sc. Lond. 



(Communicated by Dr. C. J. Martin, F.R.S. Eeceived August 11, — Eead 



November 22, 1906.) 



(From the Lister Institute of Preventive Medicine.) 



In a previous communication* it was pointed out that opsonins, whose 

 existence in relation to bacteria is generally recognised, are also produced by 

 injecting foreign red blood-cells into the peritoneal cavity. The latter 

 variety of opsonin, which is thermostable, not being destroyed by exposure 

 to 58° C. for 30 minutes, is taken up by red blood-cells of the kind used for 

 injection. Such red blood-cells, after being thus " sensibilised " by opsonin, 

 are ingested by leucocytes. 



Since it appeared obvious that the occurrence of phagocytosis might, 

 under suitable conditions of experiment, be made use of in order to discover 

 if a serum were capable of sensibilising red blood-cells, that is, if it contained 

 opsonin corresponding to the red blood-cells employed, it was determined to 

 ascertain if, proceeding along the line of investigation thus suggested, 

 a method for the estimation of red blood-cell opsonins could be devised. It 

 was further decided to study the nature of the action of such opsonins upon 

 red blood-cells. 



Estimation of Opsonin. 



In attempting to make use of phagocytosis for detecting the presence 

 of opsonin in serum a serious difficulty is at the outset encountered owing to 



* J. O. W. Barratt, "The Phagocytosis of Eed Blood- cells,"' Koy. Soc. Proc.,' B, 1905, 

 vol. 76, p. 524. 



VOL. LXXIX. — B. B 



