Re: Jill - plot thickens on adhesion

[Guest guest]

Very interesting tho I liked the previous impenetrable article even

better -g.

I think their hypothesis makes sense.

Interesting that OspC might be resopnsible for adhesion.

I didn't know some larvae ticks don't finish a blood meal and find

antoher host. Is this also ever true of nymph ticks I wonder.

As for species diversity decreasing % of bb species with OspC's that

can infect us, I don't know. Some researcher in the upper midwest

tested the squirrels adn chipmunks there...they aren't thought to be

common reservoirs...they were hugely infected. Seems like whatever's

around, bb will use as a reservoir.

> These guys

>

> http://www.genetics.org/cgi/content/full/168/2/713

>

> find that OspC allele classes are different in different vertebrate

> hosts.

>

> They say there are 22 OspC allele classes in Bb sensu stricto, that

> are all very sharply defined. Four classes can infect humans. X

> number of different ones can infect a given vertebrate species,

while

> the rest cannot. Of non-human mammals, White-footed Mouse carries a

> particularly high number of classes which are able to infect man.

It

> appears that very many wild vertebrate individuals carry every or

> almost every class its species is capable of accomodating.

>

> The function of OspC is unknown.

>

> One possible explanation they present for these observations is

that

> the adaptive immune system of vertebrate N might be particularly

good

> at recognizing a certain class of OspC, and therefore it is able to

> blast the crap out of any Bb carrying that class, thus rejecting

> infection. This strikes me as very unlikely given the great allelic

> diversity, in mice and humans alike, of the MHC molecules that

govern

> adaptive immunity.

>

> That leaves only one of the explanations they present, which is

that

> OspC pertains to adhesion. So maybe there is some unifying thing

> going on with adhesion to all the different human substrates - or

> maybe something else is going on here.

[Guest guest]

These guys point is, tho, that if the strains found in animal X are

from the wrong OspC allele groups, they apparently wont infect humans

(if you believe these guys). Ticks that feed on X will then miss one of

their few chances to acquire a human-infecting strain.

But White-footed Mouse isnt the only mammal that shares strain

suceptibilites with humans... its just the one that shares the most. So

maybe squirrels and chipmunks share one or two strains with us too.

> As for species diversity decreasing % of bb species with OspC's that

> can infect us, I don't know. Some researcher in the upper midwest

> tested the squirrels adn chipmunks there...they aren't thought to be

> common reservoirs...they were hugely infected. Seems like whatever's

> around, bb will use as a reservoir.