232 DISCUSSION 



be of the same order of magnitude as the amount of antibody that you 

 are introducing passively. These experiments are almost inevitably 

 confusing, because the cells you are transferring are also probably 

 forming antibodies, aren't they ? 



Batchelor: This is a difficulty that seems to be almost insurmountable. 

 We try to get around this by taking cells sensitized five days after graft 

 implantation ; we know that they are sensitized by this time, from a lot 

 of other evidence, and we know that their maximum antibody syn- 

 thetic capabiHty has by no means been reached by this time. I quite 

 agree that humoral antibody synthesis by transferred cells of tliis type 

 ought to be measured but we have not yet done so. 



Billingham: I should like to thank Dr. Batchelor for attempting to 

 interpret the prolongations of skin homograft survival that Dr. 

 Elizabeth Sparrow and I obtained in rabbits following intravenous 

 injection with either leucocytes or epidermal cells from the future skin 

 donor. Some years ago Dr. P. Gorer suggested that enhancement 

 might be the basis for this prolongation. Histological examination of 

 biopsy specimens from skin homografts whose survival had been con- 

 siderably prolonged by this artifice indicated that a reaction frequently 

 did occur at an early stage. Although unable to cause very rapid tissue 

 destruction, it was probably responsible for the inability of the grafts to 

 regenerate hairs. Sometimes in the centres of these grafts the epithelium 

 became weak despite the fact that the outlying epithehum, of migratory 

 origin, remained very robust. Even at the time we beUeved we were 

 deaUng with a homograft response that was only partially suppressed. 



Lawrence: In the human being at least, in the transfer of peripheral 

 blood leucocytes or their extracts, one can transfer only delayed allergy, 

 not the capacity for serum antibody formation — even to agamma- 

 globulinaemic subjects — whereas if one uses human lymph node cells 

 one can transfer both the capacity for serum antibody formation and 

 the delayed allergy. I don't know what the situation is in other mam- 

 mahan species, but perhaps by using leucocytes from the heart blood of 

 the animal it might be possible to dissociate cells that are engaged only 

 in producing delayed allergy and not transferring the capacity for 

 serum antibody. 



I would like to make another comment with respect to the role of 

 serum antibody in another system. Patterson (1962. In 2nd Inter- 



