1143. Modulation of Innate and Adaptive Immune Responses against Respiratory Viruses by Bacterial Lysates
Session: Poster Abstract Session: Innate and Adaptive Immunity to Infections
Saturday, October 22, 2011
Room: Poster Hall B1
Background: Many strategies have been developed to modulate the immune system and prevent or treat Influenza virus and Respiratory Syncytial Virus (RSV) infections. Lysates of bacteria that contain different Gram-negative and Gram-positive microorganisms could be used to positively modulate immune responses and influence the anti-viral response.

Methods: In vitro assays were performed to test bacterial lysate activity. Peripheral blood mononuclear cells (PBMCs) or THP-1 cells were stimulated with different concentrations of lysate and cytokine production was measured in the supernatants by ELISA. A mouse model was used to evaluate biological activity and antibody response modulation in respiratory viral infections. BALB/c mice were pre-treated intranasally with bacterial lysate followed by an intranasal infection with RSV or Influenza. Antibody production in serum was measured and lung histopathology was performed. 

Results: Stimulation with bacterial lysate in vitro induced the production of interleukin-6 (IL-6), IL-1β and tumor necrosis factor-α (TNF-α) in a dose dependent manner. Intranasal application of bacterial lysate in a mouse model was well tolerated. Lysate pre-treatment increased the specific antibody production in Influenza as well as RSV infections. In addition, pre-treatment with bacterial lysate polarized the anti-RSV response towards Th1. Finally, bacterial lysate did not affect inflammatory responses in the lungs during RSV infection. No evidence of worsening disease was observed in histopathology.

Conclusion: We described a novel and simple intervention that can contribute to solve the lack of protective immune responses against respiratory viruses in young infants. Bacterial products can enhance the immune response against RSV and Influenza virus, the main pediatric agents of morbidity and hospitalization worldwide.

Subject Category: E. Innate and adaptive immunity to infections, including vaccine immunology

Vera Wimmenauer, PhD1, Paula Scalzo1, David Lee2, Fernando P. Polack, MD1,2 and Silvina Coviello1, (1)Fundación INFANT, Buenos Aires, Argentina, (2)Vanderbilt University, Nashville, TN


V. Wimmenauer, None

P. Scalzo, None

D. Lee, None

F. P. Polack, None

S. Coviello, None

Findings in the abstracts are embargoed until 12:01 a.m. EST Thursday, Oct. 20 with the exception of research findings presented at IDSA press conferences.