Pulmonary cell response patterns after exposure to airborne bacteria.

The free lung cells obtained with a lavage technique were studied in guinea-pigs exposed to an aerosol of E.coli, K. pneumoniae or B.subtilis. An increase in the number of polymorphonuclear leucocytes was found 5-48 hours after exposure to E.coli and B.subtilis. The clearance of a mixture of viable and radioactively labelled E.coli was studied in animals with a naturally present or artificially induced high leucocyte level in the lungs. It was found that animals with the higher leucocyte number cleared the inhaled bacteria faster.