How much immune protection should be practically expect by vaccinating canine puppies at the age of 4-6 weeks as being claimed and advised by some drug companies?
As far as I am aware, immune protection is conferred by maternal AB until it weakens at 10 weeks to below the threshold required to mount an immune response against a foreign body such as a virus. At about 12 weeks, the maternal AB reaches a threshold where it cannot mount an immune response against a vaccine. By 14 weeks, the maternal AB is not present at detectable amounts in serum. Usually a veterinarian will administer the vaccines at 12 weeks and the puppies will develop an immune response primarily an innate response and then the adaptive response (memory).
The maternal AB interferes with the puppy's immune development because it produces an inhibitory signal by binding to the puppy's B cell at a Fc Receptor. Alternatively, the maternal AB will bind to the antigen or vaccine particle instead of the puppy's B cell (required in an adaptive immune system.) If I am wrong, please correct me.
Out of curiosity, what vaccines are offered to canine puppies at such a young age?