Results of hematological profile and serum antibody responses revealed that the challenge P. aeruginosa inhibited the immune response of all experimental rats, except negative control group, during the early acute phase of infection characterized by a significant increase count of neutrophils, lymphocytes, and monocytes but stimulated the humoral immune reaction during the chronic infection characterized by the marked increase of IgM, IgG, and IgE. This evidence concerns the gene CD40LG and infection.