Can all animals produce antibodies?

Single cell animals, ( eukariotes) don't.However, they mutate and in response to antibiotics and other substances toxic to them, they will at some point develop a gene or genes conveying immunity. read more

In multicellular animals, I cannot think of a species that doesn't produce antibodies to pathogens. It differs in the nature the antibodies ( the resistance) are transferred, as it is only transferred by inheritance, or very rare mutations. read more

Animal-Friendly Affinity reagents (AFAs) are antibodies that are generated by using recombinant technology in viruses or yeasts. The technology allows cloning of immunoglobulin gene segments, to produce antibody libraries with high diversity from which antibodies with desired specificities can be chosen. read more