J Matthew Buchanan (jbuchana at magnus.acs.ohio-state.edu) wrote:
: The loss of IL-12 production in the PBMC and not in lymphoid organ cells may be
: due to the current locale of the HIV. There is thought that the HIV localizes
: itself during stages of infection, going from a high viremia to a 'hiding'
: state in the lymph organs. It would be in teresting to see if the loss of
: IL-12 production follows the virus during a time-course study.
: The idea that distant cells could make up for the local IL-12 producito loss
: ignores the idea that cytokines acive some specificity by acitng over only very
: short distances. Thus, distant IL-12 probably remains just that, distant. A
: local loss of IL-12 would have a local loss of TH1 and CMI, not systemic.
: Possibly, this would become systemic over time, however, if enough local
: wipeouts occured.
Matt, but if enough IL-12 production is achieved in the Lymphoid
tissues, as the authors seem to be hinting then there are Th1 induction and NK
stimulation which can differentiate and proliferate and reach other sites
in the body. True that the action of Cytokines is short-distanced but the
primed cells " circulation" is not.
: In the latest Science, Fauci and another group present papers stating that they
: did not observe a loss in TH1 profiles. Il-12 was not addressed (at least not
: noticed in my first skim!). Gets more and more confusing all the time....
: The quest marches on.....
This is amazing. This finding is in Direct contradiction to Dr Jonas Salk
and Dr Peter Bretscher ( my Good old immunology professor back in
Saskatchewan) who showed evidence that as asymptomatic HIV-seropositive
individuals progress towards AIDS , there is a shift from Th1-mediated
cytokine production to a Th2-mediated one( Science Vol260:1270 28 may 1993).
This would have correlated with
the decrease in IL-12 production as the Predomninace of Th2-mediated
cytokines produces IL-10 which is a -ve regulator of IL-12.
I am gonna get a hold of last week's Science.
When will these confusing findings stop? when you get all excited about an
aspect of immunology of HIV, there comes a study to contradict it.
:Matt
:MBUCHANAN at opus.mco.edu
Cheers.
--
Shahram Mori _/\_
Program in Molecular Biology _\ /_
Dept. of chemistry and Biochemistry Box 3C \_ _/
NMSU Las Cruces NM ||
