James Crowe
Faculty Member
Last active: 3/31/2020

Cellular immune responses to diluted and undiluted aventis pasteur smallpox vaccine.

Rock MT, Yoder SM, Talbot TR, Edwards KM, Crowe JE
J Infect Dis. 2006 194 (4): 435-43

PMID: 16845626 · DOI:10.1086/505506

BACKGROUND - Recent primary vaccine trials of diluted Aventis Pasteur smallpox vaccine (APSV) demonstrated that immunization "take" rates, defined by the presence of a vesicle or pustule ("take") at the inoculation site 6-11 days after immunization, did not differ between the dilution groups. To our knowledge, there have been no studies that examine the cellular immune response or that distinguish CD4(+) T cell responses from CD8(+) T cell responses after primary immunization with varying dilutions of APSV.

METHODS - In the present study, we examined the cellular immune response in vaccinia-naive healthy adults (n=91) receiving inoculations with an undiluted or diluted (1:5 and 1:10) suspension of the APSV, using an intracellular cytokine staining assay.

RESULTS - The diluted vaccine induced vaccinia virus (VV)-specific CD4(+) and CD8(+) T cell responses 1 month after primary immunization that were comparable to those induced by undiluted vaccine. The cellular immune responses were correlated with the reactogenicity profile of subjects and did not differ between dilution groups. Furthermore, expression of the interleukin-7 receptor alpha chain, which has been proposed to distinguish antigen-specific T cells that differentiate into long-lived memory T cells, did not differ among groups, suggesting that dilution of the vaccine does not affect the quantity of VV-specific memory T cells.

CONCLUSIONS - APSV is an effective smallpox vaccine inducing strong humoral and cellular immune responses after a primary immunization even at diluted doses.

MeSH Terms (9)

CD4-Positive T-Lymphocytes CD8-Positive T-Lymphocytes Humans Interferon-gamma Lymphocyte Activation Randomized Controlled Trials as Topic Smallpox Smallpox Vaccine Vaccinia virus

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