Cynthia and lactnuts, I am coming in late on this thread, sorry, but had to add my 2 mls. I have done some searching of this topic and at one time had some private email discussions with another lactnut about this. From what I have read, I have not seen anything about directly "inoculating" the breast with the germs. Rather, the mother "breathes in" her baby with inhales and smelling him (bronchomammary pathway) and "eats him up" with kisses and finger sucks etc (enteromammary pathway) so that these mucosal surfaces (along the respiratory and GI tracts) get "inoculated" with baby's germs AND THEN the breast (on site) gets the message to make antibodies. Formula fed babies don't get this because they are not taking breastmilk. Babies eating expressed ebm should get this benefit IF THE MOM IS BREATHING HIM IN AND EATING HIM UP :) I would think cosleeping would help immensely too. Maybe there are germs going directly into the nipple pores, ascending to the ducts, etc and the breast reacting, but I have not seen this in my reading. Have said before, Would love to have an immunologist on lactnet. Laurie Wheeler, RN, MN, IBCLC Violet Louisiana, s.e. USA _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com. Share information about yourself, create your own public profile at http://profiles.msn.com. *********************************************** The LACTNET mailing list is powered by L-Soft's renowned LISTSERV(R) list management software together with L-Soft's LSMTP(TM) mailer for lightning fast mail delivery. For more information, go to: http://www.lsoft.com/LISTSERV-powered.html