Expresión de células CD11b-positivas en mucosa rectal de conejos sensibilizados y desafiados con ovoalbúmina / CD11 b-positive cells expression in rectal mucosa from ovalbumin sensitized and challenged rabbits

El receptor MAC-1 de conejo, homólogo al CD11b humano, es una proteína presente en los macrófagos. El objetivo del presente trabajo es establecer las modificaciones cuantitativas y distributivas de células CD11bpositivas participantes en la respuesta inmune a nivel de la mucosa rectal, en un modelo animal de inmunidad mucosa. Se estudiaron conejos neocelandeses divididos en tres grupos: G1:control, G2:sensibilizado con ovoalbúmina (OVA) y G3:sensibilizado y desafiado por vía rectal con OVA. Los conejos de los grupos 2 y 3 fueron sensibilizados por vía subcutánea en dos oportunidades, con 2 ml de una suspensión de 70 µg de OVA en 30 mg de hidróxido de aluminio/ml. El desafío rectal se realizó con una solución de 50 mg OVA en 5 ml de solución salina. La prueba de anafilaxia cutánea pasiva (PCA) fue positiva en G2 y G3 a una dilución de 1/160. En el grupo sensibilizado y desafiado se observó edema mucoso parcheado, imágenes de linfangiectasias e infiltración de eosinófilos. Las células se contaron como número de células por campo de mayor ...

Dermatophytoses and the high level of CR3 [CD11b/CD18]

In patients infected with dermatophytoses there is a continuous fungal antigen shedding into the circulation, especially during chronic infection, including the cell wall component beta-glucan as one of the fungal antigen. CR3 [CD1lb/CD18] serves as a leukocyte receptor for particulate and soluble beta-glucan. The keratinocyte induction by the fungus; to produce certain cytokines and their role in the upregulation of CD11 b expression. All can explain our results with the high level of CD11b expression in of Cd D11b dermatophytic expression in patients in comparison to controls group, and in chronically infected patients more than in acutely infected patients

Mac-1-mediated Uptake and Killing of Bordetella bronchiseptica by Porcine Alveolar Macrophages

The role of Mac-1 as a receptor for Bordetella bronchiseptica infection of alveolar macrophages (AMphi) was examined using 6 strains (2 ATCC and 4 pathogenic field isolates) to assess B. bronchiseptica binding, uptake and replication in primary porcine AMphi. All B. bronchiseptica strains were rapidly killed by porcine serum in a dose- and time-dependent manner. However, heat-inactivated porcine serum (HIS) did not demonstrate any bacterial-killing activity, suggesting that complement may have a direct killing activity. All field isolates were more resistant to direct complement-mediated B. bronchiseptica killing. The uptake of B. bronchiseptica into AMphi was inhibited approximately 50% by antiMac-1 monoclonal antibodies in the medium. However, B. bronchiseptica phagocytosed in the presence of serum or HIS was not altered by anti-Mac-1 antibodies although more bacteria were internalized by addition of serum or HIS. These data suggest that Mac-1 is a target for direct uptake of B. bronchiseptica via opsoninindependent binding. The phagocytosed B. bronchiseptica, either via direct or serum-mediated binding, were efficiently killed by AMphi within 10 hr postinfection. This demonstrates that Mac-1-mediated B. bronchiseptica uptake is a bacterial killing pathway not leading to productive infections in AMphi.

Enhanced eosinophil luminol-dependent chemiluminescence and complement receptor expression by platelet-activating factor and interleukin-5.

The cytokine interleukin-5 (IL-5) and the lipid mediator platelet-activating factor (PAF) have both been shown to be involved in eosinophil differentiation and activation. We have measured and compared the effect of PAF and IL-5 on human eosinophils in terms of their luminol-dependent chemiluminescence (CL) response and their expression of complement receptors, CR1 and CR3. Both IL-5 and PAF enhanced the eosinophil CL response. The optimal concentrations were 40 U/ml for IL-5, and 10(-6) M for PAF. The priming effect of IL-5 was slow and reached a maximal response after 90 minutes incubation. In contrast, the effect of PAF peaked early and declined during incubation. In the complement receptor study, only PAF was able to enhance CR3 expression (p < 0.05) while the effect of IL-5 on eosinophil complement receptor expression was negligible. These results provide evidence that both inflammatory mediator (PAF) and cytokine (IL-5) can activate eosinophils but the effects of IL-5 and PAF on eosinophil CL response appear to be distinct. The activation of eosinophils by PAF and IL-5 may occur through different mechanisms.