NOD2 signaling in CD11c + cells is critical for humoral immune responses during oral vaccination and maintaining the gut microbiome.

Nucleotide-binding oligomerization domain containing 2 (NOD2) is a critical regulator of immune responses within the gastrointestinal tract. This innate immune receptor is expressed by several cell types, including both hematopoietic and nonhematopoietic cells within the gastrointestinal tract. Vaccination targeting the gastrointestinal mucosal immune system is especially difficult due to both physical and mechanistic barriers to reaching inductive sites. The use of lactic acid bacteria is appealing due to their ability to persist within harsh conditions, expression of selected adjuvants, and manufacturing advantages. Recombinant Lactobacillus acidophilus (rLA) has shown great promise in activating the mucosal immune response with minimal impacts on the resident microbiome. To better classify the kinetics of mucosal vaccination with rLA, we utilized mice harboring knockouts of NOD2 expression specifically within CD11c + cells. The results presented here show that NOD2 signaling in CD11c + cells is necessary for mounting a humoral immune response against exogenous antigens expressed by rLA. Additionally, disruption of NOD2 signaling in these cells results in an altered bacterial microbiome profile in both control mice and mice receiving L. acidophilus strain NCK1895 and vaccine strain LaOVA.

Cerebral Candidal Abscess and Bovine Viral Diarrhoea Virus Infection in an Aborted Bovine Fetus.

Candida species are opportunistic fungi associated with immunosuppression and are the most commonly isolated fungal pathogens from the human central nervous system. Invasive candidiasis is reported uncommonly in animals and there have only been two reports of candidal infection of the brain. This report presents a case of a cerebral candidal abscess in an aborted late-term calf co-infected with bovine viral diarrhoea virus. Candida etchellsii, a species not previously identified as pathogenic, was identified as the causative agent by polymerase chain reaction.