Innate and adaptive immune responses in the intestine of camel (Camelus dromedarius) naturally infected with Mycobacterium avium subspecies paratuberculosis.

ABSTRACT

The spread of John's disease in camel herds (Camelus dromedarius) has been worldwide reported. Despite extensive studies on Mycobacterium avium subspecies paratuberculosis (MAP) infection in camels, the complete pathogenesis and epidemiology of this infection have not been fully exploited. The objective of the study is focusing on the nature of the immune responses, and the types of the recruited cells were studied in the intestine of naturally infected camels employing immunohistochemistry to analyze the expression of CD335, CD103, CD11b, and CD38 markers. Marked expression of some or all of the markers was observed in the ileum, mesenteric, and supramammary lymph nodes of the old infected camels. The expression of CD335, a well-known natural killer (NK) cell marker, was detected in the mesenteric lymph node, while the dendritic cell (DCs) marker, CD103, was markedly expressed in the villi and propria submucosa (PS) of the ileum in old infected camels. CD103 + and CD11b + DCs were detected in the mesenteric lymph nodes of young infected camels. The expression of CD38, a crucial proinflammatory marker, was more noticeable in the peripheral region of the mesenteric lymph node. The expression of these markers in the infected camel intestine was peculiar and is reported for the first time. In summary, the unique expression patterns of CD335, CD103, CD11b, and CD38 markers in naturally infected camel intestines revealed through immunohistochemistry new insights into the immune responses associated with MAP infection. These first-time observations suggest potential roles of innate and adaptive immunity, highlighting specific aspects of MAP immunopathology. Further studies with targeted tools are crucial for a precise understanding of these markers' roles in the infected intestines.