A question about Antibodies. - (Dec/18/2013 )

Antibodies are produced by Plasma B-cells, and can be found in our blood stream and secretions.

So does that mean plasma cells are producing antibodies non-stop everyday?

And can those antibodies attach to any kind of pathogens, or only just a specific one?

They only produce antibodies when they are activated, but they can remain activated for some time. The production of antibodies is geared toward a specific type of pathogen. Antibodies recognize pathogens via a particular epitope that is present on the pathogen. It is possible that an antibody can recognize different pathogens as long as they both carry the epitope that the antibody recognizes.

Maybe use the below link as a refreseher:

http://www.ncbi.nlm.nih.gov/books/NBK26884/

Decent animation showing antibody recognition:

http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter22/animation__antigenic_determinants__epitopes_.html

They only produce antibodies when they are activated. The immune system of human body has seen all antigenes during your life except two tissues:

Sperms  and  Cornea.

It means there is no immune tolerance for these two and the immune system of human body in case of any injuries would touch them and will make antibodies for attacking  and rejecting them.

The antigen binding site of an antibody is located at the top of each of the two outstretched arms. Each site is defined by 6 loops called Complementary Determining Regions (CDR). Three are found on the heavy chain (H1, H2, and H3) and 3 on the light chain (L1, L2, and L3). These protein loops mirror, or complement, the shape of specific antigens. As a result, they determine to which specific antigens the antibody can and will bind.