Dynamics of Lymphocyte Subpopulations in Immune Organs of Chickens Infected with Salmonella enteritidis

Abstract

To determine the effect of different doses of Salmonella enteritidis on immunocompetent cells, the thymus, bursa of Fabricius, and peripheral blood were examined. One-day-old chickens were orally infected with 2 × 10 2 CFU/ml (low dose) and 2 × 10 8 CFU/ml (high dose) of S. enteritidis PT4. Subsets of T lymphocytes (CD3, CD4, and CD8), and BU1b cells using an indirect immunofluorescent method and flow cytometry were analysed on days 7, 10, 14, 21, and 27 postinoculation (dpi). The actual number of lymphocytes in the peripheral blood showed a significant increase in the low dose group (P < 0.05) on day 21 pi, and in the high dose group on day 27 pi (P < 0.001) compared to controls. The increase of CD3+, CD4+, and CD8+ T cells was observed in both infected groups compared to the controls from day 14 pi, significant on day 21 pi (P < 0.05) in the high dose group. The subpopulation of CD8+ was higher also on day 27 pi (P < 0.01) compared with the values of the control group. The subpopulation of BU1b+ B cells in both infected groups showed higher values, but without significant differences from controls. The thymus T lymphocytes showed a significant decline in CD3+ T cells on day 7 pi, whereas CD4+ T cells were significantly (P < 0.05) increased on day 7 pi in both infected groups. The bursal lymphocytes showed a decrease in BU1b+ B cells in both infected groups compared with the control group, significant in the high dose group on day 21 pi (P < 0.05). These results indicate that S. enteritidis infection induced the changes in immunocompetent cells, included cellular and humoral immune response. Salmonella infection accelerated the maturation and differentiation of thymus T cells in the first phase of infection, what was secondarily reflected by increased number of studied T lymphocyte subpopulations in the peripheral blood from day 14 to 27 after infection. Similarly, it appears that the activation of B cells in bursa of Fabricius caused the decrease number of bursal B lymphocytes and increased number of these cells in the peripheral blood from day 14 to 27 pi in both infected groups.

Flow Cytometric Analysis of T cell Subset in Bursa of Fabricius in Broiler Chicken (Gallus domesticus)

“…In contrary to this Asheg et al, (2003) reported that in White Plymouth Rock chicken the Bu1b+ cell count was highest in four week-old birds and lowest in two week-old birds. CD3+ cell count was highest in two week-old birds and lowest in seven day-old birds.…”

“…As age advances, Bu-1a+ cell count also increased up to four week of age and thereafter there was a decline in the cell count. Statistically, the results showed significant difference between day-old, two week and four week-old birds but there was no significant difference in Bu-1a+ cell count between four week and six week-old birds as reported by Asheg et al, (2003) in White Plymouth Rock chicken. In all the age groups studied, Bu-1a+ cell count was more than CD3+, CD4+ and CD8+ cell count indicative of the major cell population in the bursa are B lymphocytes than CD3+, CD4+ and CD8+ T cells.…”

“…The CD4:CD8 was highest in day-old birds and lowest in two week-old birds in nonvaccinated birds, whereas Asheg et al, (2003) recorded highest CD4:CD8 in seven day-old birds and lowest in 21 day-old birds. In vaccinated group, CD4:CD8 was highest in six week-old birds and lowest in two weekold birds.…”

Live and Inactivated &lt;i&gt;Salmonella&lt;/i&gt; Enteritidis Vaccines: Immune Mechanisms in Broiler Breeders

“…There is an increased proliferation of B-lymphocytes 21 days after contact with the antigen [19], which may explain the increased levels of this cell population after immunization with the live vaccine. CD28 + T cells are T lymphocytes that have not yet undergone terminal differentiation, being still capable of replication in response to stimulus.…”

Avaliação microbiológica, histológica e imunológica de frangos de corte desafiados com Salmonella Enteritidis e Minnesota e tratados com ácidos orgânicos

“…Também, foi demonstrada redução no número de células CD4 + e CD8 + no sangue periférico de galinhas infectadas com Sallmonella Enteritidis em comparação com o grupo controle não-infectado. Neste caso, sugere-se que esse fenômeno está relacionado à migração destas células para o sitio de ação da infecção, com redução de sua expressão no sangue (Asheg et al 2003). Em aves vacinadas e submetidas à infecção com Salmonella Enteritidis, foi observado aumento da quantidade de células citotóxicas no ceco indicando saída de células da circulação com destino ao tecido desaϐiado (Berndt et al 2006).…”