We observed that independent of the isolate, dams mounted an early specific CMI response characterized mainly by an increase in the proportion of helper (CD4+) T cells at early infection (6 to 9 dpi) and cytotoxic (CD8+) T cells at late infection (9 to 20 dpi for Nc-Spain7 and 16 dpi for Nc-Spain1H). The gene discussed is CD4; the disease is infection.