Cryostat microtomy of lung tissue in an expanded state.

A technique is reported for cryostat sectioning of lung tissue in an expanded state for use in viral immunofluorescence studies. A 1:2 mixture of O.C.T. embedding compound and phosphate-buffered saline is injected intratracheally into fresh lung tissue. The lung tissue is frozen in liquid nitrogen and sectioned with a cryostat. Compared to other published reports of lung sectioning for immunofluorescence microscopy, this method has the advantages of being easy and quick, maintaining the lung sections in an expanded rather than collapsed state and avoiding contact with chemicals potentially capable of altering sensitive viral antigen.