OBJECTIVES

The leishmaniasis in cats is a disease that is, in the last few years, drawing attention in a clinical point of view as well as scientific. This is due to the major attention the clinical practitioners give to this disease, from a scientific point of view. Because it is considered as species with a natural resistance to infection with the connotations it carries. In the various projects on this pathology is known to be related with the suffering of immunosupressant diseases of feline leukaemia or feline immunodeficiency. In this study there will be carried out an immunohistochemical study (immunocharacterisation of infiltrate cells and cytokines associated with Leishmania sp infection of the cutaneous, ocular and oral lesions) to evaluate the local immune response against infection by Leishmania sp. in the cat.

MATERIALS

Material obtained by biopsy (eye, skin and oral location) were fixed in formalin and embedded in paraffin. Immunohistochemical analysis was performed using the avidin-biotin-peroxidase (ABC) method. Sections for the detection of CD3 and Ü-IgG were incubated with 0.1% for 10 min, whereas those for the detection of MHC class II were incubated in 0.01 M buffer citrate (pH 6.0) in a microwave oven (100oC) for 7 min. Tissue sections were incubated with 5% normal goat serum for 30 min. A rabbit anti-human CD3 polyclonal antibody (pAb) diluted 1 in 200 in phosphate buffered saline (PBS) pH 7.2, a rabbit anti-human IgG-lambda light chain pAb diluted 1 in 1500 in PBS, or a mouse anti-human CD79a monoclonal antibody (mAb) diluted 1 in 50 in PBS, were applied overnight at 4°C as primary antibodies. A biotinylated goat anti-rabbit immunoglobulin G diluted 1 in 200 in PBS (Vector Laboratories, Burlingame, CA, USA) was applied for 30 min as secondary reagent for primary pAb, and a biotinylated goat anti-mouse immunoglobulin G diluted 1 in 50 in PBS (Dako) was applied for 30 min as secondary reagent for the anti-MHC class II mAb.

RESULTS

The granulomatous lesions (cutaneous an ocular) showed numerous lymphocytes CD3+ in the periphery of the lesions. The lymphocytes CD3+ are situated in a diffuse manner between the macrophages and giant cells carrying amastigotes of leishmania. In the interior of the granulomatous lesions one can observe lymphocytes CD3+ isolated or in small groups. In oral lesions with few numbers of macrophages, like in the amastigote forms, showed few lymphocytes CD3+. The granulomatous lesions (cutaneous an ocular) with numerous macrophages and multinucleated giant cells with many amastigotes, showed an abundant infiltrate of plasmatic IgG+ cells in the periphery of the lesions. The oral lesions showed occasional plasmatic cells. The majority of macrophages and multinucleated giant cells exposed the antigen (Ag) MHC class II with a cytoplasmic and granular pattern. A moderate number of lymphocytes located in the periphery of the granulomatous lesions also exposed Ag MHC class II

CONCLUSION

En cases of nodular granulomatous lesions (ocular and cutaneous) an elevated number of lymphocytes CD3+ and plasmatic cells IgG+ together with an elevated expression of Ag MHC class II by numerous lymphocytes and macrophagic cells indicates a good local immune response in these animals (type IV). This response would be responsible for controlling the leishmania infection. It is confirmed that cats FIV-FeLV +, posses at least one good cellular immune response, which seems to control to development of systemic process, despite what one would think.

The oral lesions with few macrophages and lymphocytes can be the consequence of a recent infection or a residual lesion where the majority of the amastigotes forms have been destroyed.