L. E LI S P O T rea der. T he n u m ber of s p ots will be cal c ulate d p er 1 0 6 cells. U ntreate d P B M C will re pres e nt a ne gati ve c o ntr ol a n d P B M C sti m ulate d wit h 1 0 g/ ml C o n A – p ositi ve c o ntr ol. 7.