Modulation of the immune response to lipopolysaccharide

Mice given a single optimally immunogenic dose (20 micrograms) of bacterial LPS make an antibody response that is characterized by cyclic (oscillatory) patterns. This kinetic pattern is dose as well as mouse strain dependent. LPS can induce a secondary response in BALB/c mice that is also cyclic, although it differs in amplitude as well as periodicity from a primary response. To rule out the involvement of B cell mitogenic activity of LPS in the expression of such cyclic patterns, the responses produced by both C3H/HeN and C3H/HeJ mice to a single injection of LPS were compared; the latter do not give B cell proliferative responses to LPS and also have been reported to give low LPS-specific responses in vivo. Both strains gave an oscillatory kinetic pattern. By contrast, BALB/c nu/nu mice given an optimal immunogenic dose of LPS (2 micrograms) do not present a cyclic immune response. This indicates that mature T cells are required for the generation of an oscillatory anti-LPS response.