Skin bacteria may boost immune response of mice vaccinated with smallpox vaccine, study shows

Date:
April 21, 2022
Source:
PLOS
Summary:
The global eradication of smallpox in the 1980s was achieved by
intradermal vaccination with vaccinia virus. A study shows that
there is a large increase in skin bacteria and suggests that this
may enhance the immune response.



FULL STORY ==========================================================================
The global eradication of smallpox in the 1980s was achieved by
intradermal vaccination with vaccinia virus. A study published in
PLOS Pathogens by Evgeniya V. Shmeleva, Brian J. Ferguson and Geoffrey
L. Smith at University of Cambridge, United Kingdom and colleagues shows
that there is a large increase in skin bacteria and suggests that this
may enhance the immune response.


==========================================================================
The smallpox vaccination was administered via multiple skin punctures and
this method of vaccination may have introduced local bacteria into the vaccination site. However, the effect of smallpox vaccination on skin microbiota and whether these bacteria affect vaccination efficacy is
not well understood. To investigate the role of bacteria in the immune
response to smallpox vaccination, researchers used a mouse model with
germ-free mice as well as normal mice, some of which were treated with antibiotics. The mice were vaccinated with vaccinia virus, after which
the researchers analyzed the immune responses of each group.

The researchers found a 1000-fold increase in skin microbiota,
larger lesions, and higher levels of antibodies after intradermal
vaccination of mice that were not germ-free, suggesting an enhanced
skin-based inflammation response in the presence of bacteria. Germ-free
or antibiotic-treated animals had smaller infection-related lesions
and less skin inflammation. However, all groups had equal numbers of
memory T cells and similar protection from re-infection. The study was
limited to vaccination of mice with vaccinia virus and further research
is required to determine if these results in mice can be extrapolated
to either other vaccines or to vaccination of humans.

According to the authors, "This study highlights a role for commensal
bacteria in enhancing the immune response following dermal vaccination
and has implications for other vaccines based upon infectious poxviruses
or other viral vectors that are delivered by dermal vaccination."
The authors add: "We discovered that dermal vaccination with the smallpox vaccine led to a large increase in local bacteria, which increased the vaccination lesion size and affected the immune response. This suggests
that manipulation of commensal skin microbiota might be a way to enhance
the efficacy of intradermal vaccines."

========================================================================== Story Source: Materials provided by PLOS. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Evgeniya V. Shmeleva, Mercedes Gomez de Agu"ero, Josef Wagner,
Anton J.

Enright, Andrew J. Macpherson, Brian J. Ferguson, Geoffrey L. Smith.

Smallpox vaccination induces a substantial increase in
commensal skin bacteria that promote pathology and influence
the host response. PLOS Pathogens, 2022; 18 (4): e1009854 DOI:
10.1371/journal.ppat.1009854 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/04/220421141555.htm

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