hello all,i am just wondering how our immune system doesnt trigger any immune reaction against all the other components of the blood and just considering the ABO system and Rh system compatibility between the donnor and the recipient,however in the blood there are WBCs with different HLA than the reciepient.

another question why sperm are not considered as foreign organism once they enter the female body?

Excellent questions. In regard to blood transfusion, I think that the components are processed after collecting the blood so that red blood cells, platelets and plasma are separated. Moreover, leukoreduction can reduce the number of white blood cells in the blood. So I think that you can minimise the chance of rejection responses from the recipient of the blood.

http://library.med.utah.edu/WebPath/TUTORIAL/BLDBANK/BBPROC.html

 

Moreover, care is taken to match for as many antigens as possible. IMHO, the biggest problem is in preventing infections from the blood donor to the blood recipient - HIV cross infection has been a good example of this problem.

I believe sperm don't trigger an immune response because they never enter the blood stream and don't trigger cells to send the cytokine chemical alarm because they only invade the egg cell and the female reproductive tract is sterile, so the sperm won't cause an alarm since they are not doing 'infectious like' actions.

But, the vagina is, in fact, very hostile toward sperm. Something about the acidity of the environment, IIRC.

 

Only the good ones make it to the fallopian tubes. The rest (the weak runts) get killed outright by the vaginal juices (/me channels Monty Python).

The sperm is staying outside the body all the time.