system
Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: UNLABELLED, METHODS, RESULTS. Meshes: Animals, Antigens, Dinitrophenols, Enzyme-Linked Immunosorbent Assay, Haptens, Immunization, Immunoglobulin A, Secretory, Immunoglobulin G, Lymphoid Tissue, Nasal Mucosa, Nasolacrimal Duct, Rats, Rats, Inbred Lew, Serum Albumin, Bovine, Tears.
user
Is nasal-associated lymphoid tissue an absolute requirement for the induction of rat tear IgA antibody responses? Context: PURPOSE/AIM OF STUDY: The purpose of this work was to determine whether rat nasal-associated lymphoid tissue is required for the induction of tear IgA responses. Particulate antigen in the form of DNP-BSA encapsulated in cationic microparticles was applied topically to the eyes (ocular topically) of rats that had the nasolacrimal ducts temporarily plugged with chromic gut suture material. Eye washes and serum were monitored for development of antigen specific IgA and IgG, respectively. To track the particulate uptake, fluorescent latex beads were applied topically to the eyes of plugged and unplugged animals. The nasal-associated lymphoid tissue and the draining lymph nodes were then examined for the presence of the fluorescent beads. It was found that the chromic gut suture was effective in blocking the passage of antigen into the nasopharyngeal cavity for at least 24 hr. Tear antigen-specific IgA levels found in the eyes of plugged animals were not significantly lower from those of unplugged animals. Serum IgG antibody levels were also similar between the two groups. In animals with plugged nasolacrimal ducts, fluorescent beads were found predominately in the superficial cervical lymph nodes, which have been shown to drain the surface of the eye.
assistant
These results indicate that particulate antigen can be taken up by the conjunctiva and transported to the draining lymph nodes, showing that antigen does not need to access nasal-associated lymphoid tissue to induce tear IgA antibody responses. Final Decision: no