]FREQUENCY EPIDERMAL LANGERHANS CELLS IN SITE OF INTRADERMAL INJECTION PROMASTIGOTES OF Leishmania braziliensis IN MICE

Abstract

ABSTRACT We utilized immunostaining assay with Avidin Biotin Peroxidase (ABP) technique and primary rat monoclonal antibody NLDC-145 specific for mouse dendritic cell, characterized Langerhans cells (LC) in epidermis sheet of 1 mm2 of skin of the footpads of inbred females BALB/c mice, intradermally (id) injected with 1.103 cultured promastigotes of Leishmania braziliensis. The result showed that the injection of the parasites in the skin of the animals produced a progressive increment of epidermal LC in the site of the previous injection, and statistically significant (P<0.05) in each study period. The density of epidermal LC was going up by parasite insult in early time, after the 15 minutes (m) post-infection (pi) with 162± 31.2 LC/mm2, reaching a maximal value of 4503± 713 LC/mm2 to 2 week (w) pi until 898± 481 LC/mm2 to 6 w pi. The number of LC was always higher in epidermis sheet of mice infected with L. braziliensis, than in the epidermis of the control healthy mice, these skin samples showed 120± 28.9 LC/mm2. Morphological changes of the promastigotes injected could to be detected in skin Giemsa-stained imprints, the parasite showed form ovoid and a short flagel, between 15 m and 2 hour (hr) pi. No parasites were even seen in the imprint samples than of any other time of infection. These samples also showed many inflammatory cells, such as: activated macrophages (33%) to 15 m pi, neutrophils (46.33%) to 4 hr pi, eosinophils (2.33%) to 4 hr pi, lymphocytes (15.67%) to 6 hr pi, degraded lymphocytes (8.33%) to 1 w pi, monocytes (4.33%) to 5 day (d) pi and activated monocytes (19.33%) to 1 d pi. The stained sections of skin inoculated, revealed amastigotes into macrophages dermal near of the perivascular area and inflammatory process in the dermis consisted of lymphocytes, monocytes, plasma cell and polymorphonuclear cells between 1 w and 6 w pi. No parasites were detected in the epidermis. The results showed that the promastigotes in the skin survived the first 2 hr out of the macrophages, and on the other hand, stimuled various cell types in site of injection of the parasites, and the proliferation of antigen presentation by epidermal Langerhans cells, necessary for the initiation of the specific T cell immune response.