Characterization of CD4 and CD11b positive cells in lung perivascular infiltrate from ovalbumin sensitized and challenged rabbits

Rationale: We have previously demonstrated that subcutaneous sensitization with Ovalbumin (OVA) induce generation of specific IgE antibodies and modifications of immune cells populations from tracheal mucosa in rabbit. The aim of the study is characterization of CD4 and CD11b positive cell population in lung perivascular infiltrate mucosa from OVA sensitized and challenged rabbits. Methods : New Zealand white rabbits were divided into three groups: G1 (n=8): normal control; G2 (n=10): subcutaneous sensitized with OVA; G3 (n=10): subcutaneous sensitized and inhalatory challenged with OVA. Four hours after challenge animals were sacrificed and samples were processed for immunohistochemistry with the following monoclonal antibody: mouse anti-rabbit CD4 and CD11b (macrophage marker). Avidin-biotin-peroxidase system was used as detection kit. Cells were counted in 200 high power fields per group. Results : Data were expressed as arithmetic mean and standard deviation. CD4 : G1: 2,8 (SD 0,3); G2: 14,8 (SD 1,8); G3: 1,7 (SD 0,5).(G2 vs G1 and G3 p<0,001). CD11b : G1: 19,1 (SD 2,8); G2: 28,3 (SD 6,2); G3: 40,1 (SD 5,5). (G2 vs G1 p< 0,05. G3 vs. G1 and G2 p<0,05). Specific anti-OVA-IgE levels were evaluated by positive passive cutaneous anaphylaxis test (PCA) at 160 fold dilutions. Conclusion : In summary systemic sensitization with soluble antigen and inhalatory challenge induces modifications in number CD4 cells and macrophage populations in lung perivascular infiltrate. The significant increase of macrophages in challenged mucosa suggest a strong role for this cells in antigen processing and presentation.