Mucosal immunology is the study of the immune system's responses at mucosal surfaces, such as those found in the gastrointestinal tract, respiratory system, and urogenital tract. These surfaces are crucial for protecting the body from pathogens while also allowing the absorption of nutrients. The immune cells present in these areas help maintain a balance between tolerance and defense. Key components of mucosal immunology include mucosal-associated lymphoid tissue (MALT), which plays a vital role in generating immune responses. Secretory immunoglobulin A (sIgA) is an important antibody found in mucosal secretions, helping to neutralize pathogens and prevent infections. Understanding these mechanisms is essential for developing vaccines and therapies targeting mucosal diseases.