SPLEEN PROTECTION : THE CELLULAR 



HYPOTHESIS 



D. W. H. Barnes and J. F. Loutit 

 M.R.C. Radiobiological Research Unit, A.E.R.E., Harwell, Didcot, Berkshire 



It must now be incontestable that there is in spleen and bone marrow a 

 ' recovery factor ', the administration of which to otherwise lethally X- 

 irradiated mice permits their survival. Jacobson, who originally made the 

 observation, and most other workers in this field favour the hypothesis that 

 the factor is a chemical agent or hormone. 



We have not been fully convinced by their arguments and from our own 

 experimental work cannot exclude that the active principle is the transfer 



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'0 100 200 300 V-00 500 £00 700 800 SCO 



Sun^iyal time in dq/s (af zero time all micesilOO days) 



Figure I. Survival of CBA male mice 



of living cells which act for the time being at least as a tissue graft. We 

 have been concerned (7) with a dose of radiation (X-rays) which is normally 

 100 per cent lethal to our CBA strain — 950 r. Thus any survivor of treat- 

 ment is significant, and {2) with survival not only for a conventional 21 or 

 30 days but for an appreciable period thereafter. 



Under these circumstances unlike other workers we have not been able 

 to obtain recovery with heterospecific material — spleen or bone marrow 

 from rabbits and guinea pigs^ 



Latterly we have reported our results with homospecific but heterologous 

 mouse spleen^. Spleen of strain A mice given to our standard test animals 

 of the CBA strain gave a significant survival rate (9/16) at 30 days, but this 

 early success was not maintained and all survivors were dead by 100-odd 

 days. This is to be contrasted with the administration of homologous 

 mouse spleen from donors of strain CBA. Here the median life expectation 



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