A procedure for pulmonary lavage in mice.

A method for the pulmonary lavage of mice is described. The procedure includes exsanguination of anesthetized mice by severting the renal artery, inserting a tracheal catheter in situ, and repeatedly injecting and aspirating 0.9% sodium chloride solution. Protein was recovered from the cell-free lavage fluid even after a given mouse was lavaged several times. The major part of the protein, however, was obtained with 1-ml washes repeated 3 times. Approximately 0.563 mg of protein was recovered by the procedure from a 29-g mouse. Four lavages per mouse yielded approximately 2.9 x 106 free cells.

Relationship of antimicrobial cellular immunity to delayed hypersensitivity in Listeriosis.

The relationship of antimicrobial cellular immunity to delayed hypersensitivity (DH) was studied in mice antigenically stimulated by living Listeria monocytogenes confined to diffusion chambers in peritoneal cavities or by subcutaneous inoculation of sublethal doses of the organism. Mice showed DH reactions when tested 6 days after inoculation, and reactions were positive for at least 90 days in some mice. DH also became established when the mice were stimulated by antigens diffusing from peritoneal chambers containing viable Listeria. Mice were categorized as DH positive or DH negative if they developed more or less than a 5% increase in foot volume 24 h after the injection of Listeria antigen. Some antigenically stimulated mice did not elicit the DH reaction. Consequently, the animals were arranged as immunized groups (DH positive and DH negative) and Listeria chamber implant groups (DH positive and DH negative). When challenged with L. monocytogenes, all four groups were significantly resistant as compared with controls. Thus, the in vivo tests for immunity and DH did not show direct correlation. The results suggested that antimicrobial cellular immunity can occur as a phenomenon independent of DH. Evidence for antimicrobial cellular immunity as the principle mechanism of resistance in murine listeriosis is discussed with consideration for possible heterogeneity of function by thymus-derived lymphocytes.

Immunochemical analysis of serum-related proteins in the respiratory tract secretions of normal mice.

Normal mouse lung lavage fluid was analyzed for its content of serum-related proteins by the methods of gel filtration, immunoelectrophoresis, and double immunodiffusion. Lavage samples were collected from exsanguinated mice using three repeated infusions of 0.9% sodium chloride solution. Cells were removed, and the lavage fluid was concentrated. Approximately 0.23 mg of protein per mouse was present in the concentrated solution. Albumin, transferrin, and immunoglobulin G (IgG) were among the proteins in greatest concentration. Albumin, IgG1, IgG2, IgA, and IgM were quantitated by single radial diffusion. Although immunoglobulins could be synthesized locally, albumin and transferrin were assumed to come from plasma. The albumin content was used to estimate the amount of transudated plasma as 0.0027 ml per mouse. The IgA levels were low with an IgA/IgG1 ratio of 0.58 and an IgA/IgG2 ratio of 0.43. IgM was not detected. Goat anti-lung lavage serum revealed the presence of additional lung-related proteins.