TFRC and influenza: More important, it has been suggested that Tfr cells control different aspects of humoral immune response to foreign antigens at specific stages of the GC reaction, viz., they have a major influence on the magnitude of antibody response to foreign antigens at early stages of the immune response, whereas at later stages (e.g., 36 days after influenza infection and beyond) they control the specificity of the antibody response [77,78,79,80].