Cellular and Cytokine Responses in Lymph Node Granulomas of Bacillus Calmette Guérin (BCG)-Vaccinated and Non-vaccinated Cross-Breed Calves Naturally Infected With Mycobacterium bovis

Cytokine Dysregulation in pulmonary Tuberculosis: The role of TNF-α/IL-10 and TNF-α/TGF-β ratios as severity indicators

BACKGROUND

In human tuberculosis, Mycobacterium tuberculosis elicits immunopathology characterized by abnormal expression of plasma cytokines. This immunopathology may influence the severity of illness and the efficacy of prolonged anti-mycobacterial treatment.

METHODS

The study analysed TNF-α, IL-10, and TGF-β levels in 90 pulmonary tuberculosis patients and compared them with 90 healthy individuals. The tuberculosis patients were categorized as mild, moderate, or advanced based on chest x-ray results, and the ratio of pro-inflammatory to anti-inflammatory cytokines was compared.

RESULTS

All three cytokines were present in most tuberculosis patients, and their concentrations were noticeably higher than in healthy individuals. The ratio of TNF-α/IL-0 and TNF-α/TGF-β demonstrated the most powerful discriminatory ability in determining the severity of tuberculosis. The levels of TNF-α/IL-0 and TNF-α/TGF-β in individuals with moderate and advanced tuberculosis were markedly elevated compared to those with mild cases. The area under the curve (AUC) for TNF-α/TGF-β and TNF-α/IL-0 was determined to be 0.823 and 0.814, respectively.

CONCLUSIONS

The elevated ratio of TNF-α/IL-0 and TNF-α/TGF-β in the sera of TB patients may contribute to an excessive pro-inflammatory response, whereas a lower ratio may regulate excessive inflammation. Both the TNF-α/IL-0 and TNF-α/TGF-β ratios may effectively categorize the tuberculosis severity and have the potential to serve as biomarkers for evaluating the early response to treatment.

Holstein × Montbéliarde-sired F1 generation crossbred female calves have an increased cellular immune response potential compared with purebred Holsteins

It is well known that crossbreds show many advantages over purebreds in improving calf health traits, but the immunological factors responsible for this heterosis remain largely unclear. The objective of this study was to compare the cellular immune responses and antibodies of Holstein (HO) and Montbéliarde-sired × Holstein (MH) F1 generation female calves, and investigate the effects of crossbreeding on the immunity. Fifty three-month-old healthy female calves (25 HO, 25 MH) were selected meticulously in a farm with the same criteria. Subsequently, complete blood count, flow cytometric analysis of T cell subsets and intracellular IFN-γ production, as well as indirect ELISA analysis of antibodies were performed in order to determine the immune profiles of the two groups of calves. We found that MH calves had higher percentage and number of CD4+ and CD8+ T cells than HO calves in the peripheral blood (p < 0.05), with higher MFI of CD44 on CD4+ and CD8+ T cells (p < 0.05). When stimulated by PMA and Ionomycin, the CD4+ and CD8+ T cells from MH calves secreted more IFN-γ than that of HO calves (p < 0.01). These results suggested that some immunological traits have been improved in MH calves, which may be an important cause of heterosis in crossbred animals.

Histopathologic differences in granulomas of Mycobacterium bovis bacille Calmette Guérin (BCG) vaccinated and non-vaccinated cattle with bovine tuberculosis

Mycobacterium bovis (M. bovis) is the zoonotic bacterium responsible for bovine tuberculosis. An attenuated form of M. bovis, Bacillus Calmette-Guerin (BCG), is a modified live vaccine known to provide variable protection in cattle and other species. Protection for this vaccine is defined as a reduction in disease severity rather than prevention of infection and is determined by evaluation of the characteristic lesion of tuberculosis: the granuloma. Despite its recognized ability to decrease disease severity, the mechanism by which BCG imparts protection remains poorly understood. Understanding the histopathologic differences between granulomas which form in BCG vaccinates compared to non-vaccinates may help identify how BCG imparts protection and lead to an improved vaccine. Utilizing special stains and image analysis software, we examined 88 lymph nodes obtained from BGC-vaccinated and non-vaccinated animals experimentally infected with M. bovis. We evaluated the number of granulomas, their size, severity (grade), density of multinucleated giant cells (MNGC), and the amounts of necrosis, mineralization, and fibrosis. BCG vaccinates had fewer granulomas overall and smaller high-grade granulomas with less necrosis than non-vaccinates. The relative numbers of high- and low- grade lesions were similar as were the amounts of mineralization and the density of MNGC. The amount of fibrosis was higher in low-grade granulomas from vaccinates compared to non-vaccinates. Collectively, these findings suggest that BCG vaccination reduces bacterial establishment, resulting in the formation of fewer granulomas. In granulomas that form, BCG has a protective effect by containing their size, reducing the relative amount of necrosis, and increasing fibrosis in low-grade lesions. Vaccination did not affect the amount of mineralization or density of MNGC.