Recruitment of lymphocytes and dendritic cells from the blood to the bronchoalveolar space and the draining lymph nodes after a single intrabronchial application of the lipopeptide MALP-2.

OBJECTIVE

It has been shown previously that the synthetic macrophage-activating lipopeptide, MALP-2, is a potent stimulator of the respiratory immune system and an effective adjuvant in the induction of mucosal immune responses. In this study, the migration route of leukocytes from the blood to the bronchoalveolar space and then to the draining lymph nodes was investigated.

METHODS

MALP-2 was intratracheally instilled into lungs of Lewis rats. Bronchoalveolar lavage cells as well as cell preparations of other lung compartments such as the marginal vascular pool, the interstitial pool and also the draining lymph nodes were examined 3 days later.

RESULTS

The application of MALP-2 induced a pronounced leukocyte accumulation in the bronchoalveolar space and the lung interstitium but not in the marginal vascular pool. A tendency to increased lymphocyte and dendritic cell numbers was observed in the draining lymph nodes.

CONCLUSION

Our data indicate the migration of blood cells into the lung interstitium and the bronchoalveolar space in response to MALP-2. Thus, the immune reaction induced by MALP-2 might be of relevance as an adjuvant treatment in inhalant vaccination strategies in the lung.