Flows induced by the surface tension gradient (Marangoni effects), which can be generated in the specific gas-liquid system of the pulmonary surfactant in the human lungs, are discussed. The pulmonary liquid starts to flow as a result of local surfactant depletion due to its adsorption on small solid particles, which arrive to the system with the breathing air. Mathematical model of this phenomenon is presented and solved to demonstrate that a strong hydrodynamic signal is induced due to the presence of the surface-active monolayer. Considering the specific features of the analyzed physiological system of the pulmonary surfactant, it is hypothesized that such microflow can stimulate the phagocyte cells (alveolar macrophages) existing in the liquid for movement in the direction of the particle, what will accelerate natural defense mechanisms. Possible ways of verification of the hypothesis are briefly discussed.