Lipopolysaccharide augments IgG and IgE responses of mice to the latex allergen Hev b 5

Background: LPS is a common contaminant in the health care environment and in latex examination gloves. Objective: We sought to investigate the role of LPS in enhancing the immune responses of mice to inhaled latex allergen. Methods: As our model allergen, we used a fusion protein containing the potent latex allergen Hev b 5. BALB/c mice were lightly anesthetized and given repeated intranasal doses of saline, LPS, and/or Hev b 5. The doses were given in 2 courses separated by a 6-week period, with the first course consisting of 6 doses and the second consisting of 3 doses. Results: After the first set of immunizations, mice given Hev b 5 alone had no detectable IgG1 or IgE responses to Hev b 5, whereas mice given the antigen along with LPS had significant responses (IgG1, 0.73 U +/- 0.05; IgE, 0.88 U +/- 0.2). No enhancement of specific IgG2a was observed. A stimulatory effect of LPS on all 3 immunoglobulin types was apparent after the second course. Lymphocytes from mice immunized with LPS and Hev b 5 had increased proliferation to Hev b 5 and its fusion partner. Conclusions: LPS may be an important immunoadjuvant for the development of allergic reactions to latex protein allergens.