Rabbits immunized to different antigens (bacteriophage T4, bovine serum albumin, and keyhole limpet hemocyanin), in which presence of antibodies in serum had been proved, were checked for presence of antibodies in tears. Using different techniques, the presence of antibodies in tears was found in all rabbits checked. The most sensitive technique was passive hemagglutination with five positive results out of five animals checked. Passive cutaneous anaphylaxis showed three positive results out of five. Ouchterlony showed zero positive out of four and phage neutralization assay showed one out of one.
Sapse AT, Ivanyi J, Stone W, Bonavida B, Sercarz EE. Tears as Carriers of AntibodiesI. Presence of Antibodies to Diverse Antigens in Rabbit Tears. Arch Ophthalmol. 1967;77(4):526-529. doi:10.1001/archopht.1967.00980020528016