Analysis of functional heterogeneity of porcine memory CD4+ T cells

Previous studies have identified swine helper memory T cells as CD4(+) CD8alpha(+) SLADR(+). We have recently described a new porcine surface antigen (2E3) selectively expressed on CD4(+) T cells that allows to divide these cells into naive (2E3(+)) and effector/memory (2E3(-)). However, although the majority of CD4(+)2E3(-) cells are CD8alpha(+)SLADR(+), a minor proportion do not express SLADR and/or CD8alpha. Here, we have analyzed the functional capacity of these CD4(+)2E3(-) subsets to proliferate to a recall antigen. Both SLADR(-) and CD8alpha(-) cells proliferated in response to lysozyme, but at lower levels compared to the whole population CD4(+) 2E3(-). Besides, after activation with PMA plus ionomycin, CD4(+) 2E3(-) SLADR(-) T cells produced IFNgamma and TNFalpha, although they did also in lower proportion than the whole CD4(+)2E3(-) population. Most of the IFNgamma(-)TNFalpha(+), IFNgamma(+)TNFalpha(+), IFNgamma(+)TNFalpha(-) cells were CD8alpha(+) and CD45RA(-), while IFNgamma(-)TNFalpha(-) cells showed a less differentiate phenotype. (C) 2004 Elsevier Ltd. All rights reserved.