PMID- 38240274 OWN - NLM STAT- MEDLINE DCOM- 20240701 LR - 20250327 IS - 1544-2217 (Electronic) IS - 0300-9858 (Print) IS - 0300-9858 (Linking) VI - 61 IP - 4 DP - 2024 Jul TI - Immunohistochemical characterization of the immune cell response during chlamydial infection in the male and female koala (Phascolarctos cinereus) reproductive tract. PG - 621-632 LID - 10.1177/03009858231225499 [doi] AB - Chlamydiosis is one of the main causes of the progressive decline of koala populations in eastern Australia. While histologic, immunologic, and molecular studies have provided insights into the basic function of the koala immune system, the in situ immune cell signatures during chlamydial infection of the reproductive tract in koalas have not been investigated. Thirty-two female koalas and 47 males presented to wildlife hospitals with clinical signs suggestive of Chlamydia infection were euthanized with the entire reproductive tract collected for histology; immunohistochemistry (IHC) for T-cell (CD3epsilon, CD4, and CD8alpha), B-cell (CD79b), and human leukocyte antigen (HLA)-DR markers; and quantitative real-time polymerase chain reaction (rtPCR) for Chlamydia pecorum. T-cells, B-cells, and HLA-DR-positive cells were observed in both the lower and upper reproductive tracts of male and female koalas with a statistically significant associations between the degree of the inflammatory reaction; the number of CD3, CD4, CD79b, and HLA-DR positive cells; and the PCR load. CD4-positive cells were negatively associated with the severity of the gross lesions. The distribution of immune cells was also variable according to the location within the genital tract in both male and female koalas. These preliminary results represent a step forward towards further exploring mechanisms behind chlamydial infection immunopathogenesis, thus providing valuable information about the immune response and infectious diseases in free-ranging koalas. FAU - Pagliarani, Sara AU - Pagliarani S AUID- ORCID: 0000-0003-1415-0299 AD - The University of Queensland, Gatton, QLD, Australia. AD - University of Guelph, Guelph, ON, Canada. FAU - Johnston, Stephen D AU - Johnston SD AD - The University of Queensland, Gatton, QLD, Australia. FAU - Beagley, Kenneth W AU - Beagley KW AD - Queensland University of Technology, Brisbane, QLD, Australia. FAU - Palmieri, Chiara AU - Palmieri C AUID- ORCID: 0000-0002-5791-6066 AD - The University of Queensland, Gatton, QLD, Australia. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20240119 PL - United States TA - Vet Pathol JT - Veterinary pathology JID - 0312020 RN - 0 (HLA-DR Antigens) SB - IM MH - Animals MH - *Phascolarctidae/microbiology MH - Female MH - *Chlamydia Infections/veterinary/immunology/pathology/microbiology MH - Male MH - *Immunohistochemistry/veterinary MH - *Chlamydia/immunology MH - Reproductive Tract Infections/veterinary/microbiology/pathology/immunology MH - B-Lymphocytes/immunology/pathology MH - HLA-DR Antigens/metabolism MH - Australia MH - T-Lymphocytes/immunology PMC - PMC11264539 OTO - NOTNLM OT - PCR OT - chlamydiosis OT - histology OT - immunohistochemistry OT - koala OT - reproductive tract COIS- Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. EDAT- 2024/01/19 12:44 MHDA- 2024/07/01 06:42 PMCR- 2024/07/23 CRDT- 2024/01/19 08:15 PHST- 2024/07/01 06:42 [medline] PHST- 2024/01/19 12:44 [pubmed] PHST- 2024/01/19 08:15 [entrez] PHST- 2024/07/23 00:00 [pmc-release] AID - 10.1177_03009858231225499 [pii] AID - 10.1177/03009858231225499 [doi] PST - ppublish SO - Vet Pathol. 2024 Jul;61(4):621-632. doi: 10.1177/03009858231225499. Epub 2024 Jan 19.