Flow Cytometric Evaluation of CD4+ and CD8+ T-cell Immune Response in SPF Chickens Induced by Fowlpox Vaccine

Document Type : Original Articles


1 Department of Microbiology, Faculty of Sciences, Islamic Azad University, Karaj Branch, Karaj, Iran

2 Department of Research & Development, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran

3 Department of Brucella Vaccines Production, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran

4 Department of Poultry Vaccines Production, Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran


Fowlpox (FP) is a viral disease that is widely distributed throughout the world. The disease has an economic impact on the poultry industry, and its prevalence has even been reported in vaccinated flocks. The present study used flow cytometry to evaluate the CD4+ and CD8+ T-cell immune response of chicks induced by FP vaccine. 120 specific pathogen-free (SPF) 21-day-old chicks were randomly divided into three groups of 40. One group was used as negative control with PBS inoculation, the other two groups were inoculated with the local fowlpox vaccine produced by Razi Institute and commercial FP vaccines, and they were kept for five weeks. Peripheral blood mononuclear cells (PBMC) were isolated using Ficoll–Hypaque density gradients and the percentages of CD3+, CD3+, CD4+, and CD3+CD8+ T lymphocytes were analyzed with flow cytometry. Seven days post-immunization, a maximum (90-100%) swelling formation (“take”) on the vaccination site was observed. The ratios of CD4+ to CD8+ T-lymphocytes in both vaccinated groups were significantly higher (p < 0.05) than the control group inoculated with PBS. The percentages of CD3+, CD3+CD4+, and CD3+CD8+ T-lymphocytes were increased in chickens vaccinated with commercial and local FP vaccines. There were no significant differences between the groups receiving commercial and local fowl pox vaccines. The present study showed that protective immunity could be associated with increased cellular immune responses, which has been interpreted as enhancing T-cell proliferation and increasing CD4+ to CD8+ ratios through vaccination with the FP vaccine. This study further suggests that the induction of enhanced immune responses is due mainly to the Th1-type response.


Article Title [French]

Évaluation Cytométrique en flux de la Réponse Immunitaire des Lymphocytes T CD4+ et CD8+ chez les Poulets SPF Induite par le Vaccin de la Variole

Abstract [French]

La variole est une maladie virale largement répandue dans le monde. La maladie a un impact économique sur l'industrie avicole et sa prévalence a même été rapportée dans des troupeaux vaccinés. La présente étude a utilisé la cytométrie en flux pour évaluer la réponse immunitaire cellulaire des lymphocytes T CD4+ et CD8+ des poussins induite par le vaccin de la variole. 120 poussins de 21 jours exempts d'agents pathogènes spécifiques (SPF) ont été répartis au hasard en trois groupes de 40. Un groupe a été utilisé comme contrôle négatif avec une inoculation du PBS, les deux autres groupes ont été inoculés avec le vaccin local contre la variole aviaire produit par l'Institute Razi et des vaccins commerciaux de la variole, et ils ont été conservés pendant cinq semaines. Les cellules mononuclées du sang périphérique (CMSP) ont été isolées à l'aide de gradients de densité Ficoll-Hypaque et les pourcentages de lymphocytes T CD3+, CD3+CD4+ et CD3+CD8+ ont été analysés par cytométrie en flux. Sept jours après l'immunisation, une formation de gonflement maximale (90-100 %) ("prise") sur le site de vaccination a été observée. Les ratios de lymphocytes T CD4+ à CD8+ dans les deux groupes vaccinés étaient significativement plus élevés (p<0.05) que le groupe témoin inoculé avec du PBS. Les pourcentages de lymphocytes T CD3+, CD3+CD4+ et CD3+CD8+ ont été augmentés chez les poulets vaccinés avec des vaccins commerciaux et locaux de la variole. Il n'y avait pas de différences significatives entre les groupes recevant des vaccins commerciaux et locaux contre la variole aviaire. La présente étude a montré que l'immunité protectrice pourrait être associée à une augmentation des réponses immunitaires cellulaires, qui a été interprétée comme une augmentation de la prolifération des lymphocytes T et une augmentation des rapports CD4+ à CD8+ grâce à la vaccination avec le vaccin de la variole. Cette étude suggère en outre que l'induction de réponses immunitaires améliorées est principalement due à la réponse de type Th1.

Keywords [French]

  • vaccin contre la variole aviaire
  • lymphocytes T CD4+/CD8+
  • poulets SPF
  • cytométrie en flux
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