360 PAUL S. RUSSELL 



the signs of ruiit disease. Two may have shown some transient and 

 late effects of the injection but all of the survivors reacted in a 

 normal fashion to grafts of DBA skin when they had reached 

 six weeks of age. Subcutaneous inoculation gave similar results. 

 (3) Spleen cells from donors previously sensitized to the recipient 

 strain. It is readily possible in the present strain combination to 

 demonstrate acceleration of the graft-versus-host reaction by the 

 use of spleens from donor animals which have previously rejected 

 skin grafts of recipient strain origin (Billingham, 1958). For 

 example, all six of a litter of C57BL/6 animals treated with 15 

 million DBA/i spleen cells from donors which had fully rejected 

 bilateral C57BL/6 skin grafts a week previously were dead by the 

 twelfth day. This contrasts with an expected median survival of 

 about 14 days when cells from untreated donors are used. The 

 weight-gain curve shows little difference in these two situations, 

 both of which involve disease of such an acute type that differences 

 are difficult to distinguish. 



II. Effect of some specific treatments directed against the 

 foreign cell population 



As outlined above, the specific treatments designed to destroy 

 or inactivate only the runt-producing population of spleen cells in 

 neonatal animals with impending runt disease involved either the 

 adoptive transfer of a second inoculum of adult spleen cells from 

 donors isologous with the test animals, or the transfer of serum 

 from isologous adults previously sensitized to DBA/i tissues. 

 Cells from sensitized donors were also used. 



(i) Adoptive transfer of protective cells. Initially the efficacy of 

 adult isologous cells was tested by intravenously administering, 

 on the first day of life, a mixture of approximately equal numbers 

 of DBA/ 1 and C57BL/6 spleen cells. Almost all animals receiving 

 such a cell mixture, including a dose of DBA/ 1 cells entirely 

 adequate to produce runt disease under ordinary circumstances, 

 gave no evidence whatsoever of the disease. This was true when 



