Transport of water and solutes across bullfrog alveolar epithelium

Water and solute transport properties of the alveolar epithelium of isolated bullfrog lungs were studied. Lungs from Rana catesbeiana were removed and mounted in an Ussing chamber. Unstirred layers on both sides of the tissue were estimated from the time courses of dilution potential development, and the measured transport parameters were corrected for the effect of the unstirred layers. Spontaneous potential difference, short-circuit current, tissue resistance, instantaneous voltage-current relationships, diffusional permeabilities of water and hydrophilic solutes, and hydraulic conductivities were determined. The hydraulic conductivity obtained from hydrostatically driven water flow anomalously decreased with time, and was initially 100 -1,000 times higher than osmotically determined hydraulic conductivity. The equivalent pore radius of the bullfrog alveolar epithelium was estimated to be 0.8-0.9 nm. We conclude that the alveolar epithelium is extremely tight, presenting a major barrier to water and solute flow. This high resistance to water and solute flow may be helpful in maintaining the alveolar lumen relatively free of fluid under normal physiological conditions.

Monoclonal antibodies to stage-specific, species-specific, and cross-reactive antigens of the rodent malarial parasite, Plasmodium yoelii

Eighteen hybridoma cell lines were used to study species-specific, stage-specific, and serological cross-reactive antigens of the rodent malarial parasite, Plasmodium yoelii. Specificity and location of plasmodial antigens were determined by indirect fluorescent-antibody analysis. Results showed that a minimum of 12 distinct plasmodial antigens could be distinguished by the 18 hybridomas. Antigens were found on the surface or within the cytoplasm of the parasite, but not on the surface of erythrocytes from infected animals. The majority (11 of 12) of antigens were present in all erythrocytic stages of the parasite, but one was stage-specific for merozoites. Additional studies showed that 6 of 18 of the monoclonal antibodies identified species-specific antigens, 2 of 18 recognized antigens confined to related rodent malarial parasites (Plasmodium berghei, Plasmodium vinckei, and Plasmodium chabaudi), whereas 8 of 18 detected cross-reactive antigens common to rodent, primate (Plasmodium knowlesi, Plasmodium falciparum), and avian (Plasmodium gallinaceum) malarias.

Radioimmunoassay for detecting antibodies against murine malarial parasite antigens: monoclonal antibodies recognizing Plasmodium yoelii antigens

A solid-phase radioimmunoassay (SPRIA) in microtiter wells was established for detecting antibodies against Plasmodium yoelii Ag. The SPRIA was found 1) to require as little as 5 micrograms of crude parasite Ag per well, 2) to be able to detect 0.5 ng of monoclonal Ab, and 3) to be 10(4) times more sensitive than the indirect fluorescent Ab staining technique. In a modification of the above assay using intact RBC as an Ag, hyperimmune serum showed significant binding to the surface of erythrocytes of mice infected with P. yoelii parasites but not to RBC of normal mice. Hybridomas were prepared by fusing infected mouse spleen cells with P3-NS1/I-Ag4-1 myeloma cells. Using the SPRIA, hybrids secreting Ab against P. yoelii 17XL Ag were detected. All the hybrids detected by SPRIA secreted Ab binding to free parasites but not to the surface membrane Ag on the infected RBC. The number of positive hybrids produced by fusing spleen cells from mice given a double infection (17XNL and 17 XL) was not greater than that produced by freezing spleen cells from mice given a single infection (17 XL).

Radioimmunoassay for detecting antibodies against murine malarial parasite antigens: monoclonal antibodies recognizing Plasmodium yoelii antigens

A solid-phase radioimmunoassay (SPRIA) in microtiter wells was established for detecting antibodies against Plasmodium yoelii Ag. The SPRIA was found 1) to require as little as 5 micrograms of crude parasite Ag per well, 2) to be able to detect 0.5 ng of monoclonal Ab, and 3) to be 10(4) times more sensitive than the indirect fluorescent Ab staining technique. In a modification of the above assay using intact RBC as an Ag, hyperimmune serum showed significant binding to the surface of erythrocytes of mice infected with P. yoelii parasites but not to RBC of normal mice. Hybridomas were prepared by fusing infected mouse spleen cells with P3-NS1/I-Ag4-1 myeloma cells. Using the SPRIA, hybrids secreting Ab against P. yoelii 17XL Ag were detected. All the hybrids detected by SPRIA secreted Ab binding to free parasites but not to the surface membrane Ag on the infected RBC. The number of positive hybrids produced by fusing spleen cells from mice given a double infection (17XNL and 17 XL) was not greater than that produced by freezing spleen cells from mice given a single infection (17 XL).

Transport of water and solutes across sheep visceral pleura

The fluid and solute transport properties of pleural tissue were studied using specimens of intact visceral pleura from adult sheep lungs. After thoracotomy, a shallow incision through the pleural surface permitted 10-cm2 by 10-micrometer pieces of visceral pleura free of lung parenchyma to be peeled off the lung surface. The pleura was then mounted as a planar sheet separating 2 reservoirs of Krebs-Ringer solution. Electrical potential and resistance, hydraulic water permeability, and diffusional permeability to water and several hydrophilic solutes were measured. The results showed that (1) no spontaneous voltage difference was present across the pleura; (2) electrical resistance (27.1 omega/cm2) was very low; (3) hydraulic water permeability was extremely high (1.64 X 10(-8) ml/dyne-s); and (4) diffusional permeability was high, varying from 5.24 X 10(-4) cm/s for water to 4 X 10(-5) cm/s for hemoglobin. Blue dextran (molecular weight, 2 X 10(6) daltons) did not cross the pleura in measurable quantities. We concluded that the isolated visceral pleura of the adult sheep is an extremely "leaky" tissue that probably does not actively transport salt and water. These findings are consistent with a passive model of pleural fluid formation and reabsorption, and suggest that the transport properties of normal pleural tissue are unlikely to be responsible for any differences in composition between interstitial and pleural fluids.

Generation of anti-type III pneumococcal polysaccharide hybridomas from mice with an X-linked B-lymphocyte defect

(CBA/N X BALB/c male)F1 mice bear on X-linked defect making them totally unresponsive to T-independent (TI), TI-2 antigens such as type III pneumococcal polysaccharide (SSS-III). We found that somatic cell hybrids between CB nonresponder spleen cells and NS1 plasmacytoma cells secreted antibody specific for SSS-III. The solid-phase binding of such antibody was completely inhibited by the addition of free antigen (SSS-III) and the amount of antibody detected in culture fluids ranged from 10 ng/ml to 10 micrograms/ml. Eight hybridoma clones were identified; all make antibody of the IgM class. These results indicate that the X-linked defect does not result in a deletion of a B-cell subset which responds to TI-2 antigens.

Macrophage cell lines produce a cytotoxin

Cytotoxic activity, measured by release of tritium from 3H-(methyl)-thymidine-labeled 7943 cells, was found in culture fluids from four of five macrophage cell lines. In the P388D1 cell line, cytotoxic activity was highest after 7 days of culture, 2 days after the cells reached confluence. The activity was not lost upon dialysis or lyophilization. When culture fluids were chromatographed on Sephadex G-200, two activity peaks were obtained: one in the void volume and the other corresponding to a m.w. of 40,000 to 50,000.

Two spontaneous BALB/c lymphomas synthesize IgM: monomers and half molecules are isolated and characterized whereas another molecule resembles IgD

Spontaneous lymphomas of BALB/c mice, both in vivo tumors and cell lines established in long term tissue cultures, were investigated for their ability to synthesize IgM by using radiolabeled amino acid precursors. Immunoglobulins manufactured by lymphomas K46 and L10A had the m.w. of monomeric IgM and IgM half molecule. Both of these molecules could be immunoprecipitated with class-specific anti-IgM but not anti-IgA or anti-IgG. When precipitated with polyvalent anti-Ig L10A synthesized monomeric immunoglobulins that migrated as two peaks in contrast to their single counterpart precipitated with anti-IgM. The second peak migrated in the region expected for IgD. Monomer and half molecules were composed of similar ratios of mu-chains to light chains linked by disulfide bonds. The mu2L2 monomer of these B cell lines migrated slightly slower in SDS PAGE than a mu2L2 secreted by a myeloma. Thus, these lymphomas synthesize immunoglobulins with the chemical and antigenic characteristics typical of monomeric membrane-attached IgM and IgM half molecules, plus a molecule resembling IgD on L10A only. Lymphoma assembly of monomeric IgM may follow the same initial biosynthetic sequence as myeloma assembly.

Induction of amplified synthesis and secretion of IgM by fusion of murine 'b lymphoma with myeloma cells

Murine B lymphoma cultured cell lines bearing membrane IgM and lacking the ability to secrete measurable amounts of IgM were fused with drug-resistant cell lines derived from the IgG2b-producing MPC-11 myeloma. Many of the hybrid clones synthesized and secreted large amounts of IgM, as judged by radial and double immunodiffusion in agar of culture supernatants and by polyacrylamide gel electrophoresis of biosynthetically labeled IgM. When fused with an IgG2b-producing myeloma, many of the hybrids also produced IgG2b, indicating that there was no suppression of the parental IgG synthesis in the hybrids. The amount of IgM or IgG2b secreted by the hybrids was higher than that secreted by myeloma cell lines. The synthesis of the gamma2b heavy chain of the MPC-11 myeloma was not reexpressed by fusion of a gamma2b nonproducer myeloma cell variant with B lymphoma. No other classes of Ig heavy chains, besides the gamma2b and the mu chains, were found to be secreted by any of more than 100 B lymphoma--myeloma hybrids examined. The results of the present work suggest that myeloma cells may fuse not only with normal plasma cells but also with less-mature normal B lymphocytes and that this fusion "induces" the maturation of B lymphocytes into IgM-secreting cells.

Functional characteristics of BALB/c T cell lines: suppression in the mixed lymphocyte response and cell-mediated lysis

Previously, 10 BALB/c T cell lines (Thy 1.2+, Ig-) were shown to express different combinations of Ly 1 and Ly 2 antigens. The possible immunologic function(s) of these tumor cells was determined by investigating the effects of these cells on the responses to mitogens, the mixed lymphocyte response (MLR), and the generation of cell-mediated lysis (CML) by normal spleen cells. Five T cell lines, P1798 and BALENTL 3, 5, 8, and 9, continued to synthesize DNA after exposure to large doses of irradiation. Only BALENTL 4, 6, 7, and 14 (Ly 1-(2+)) and BALENTL 13 (Ly 1+(2-)) were radiosensitive and therefore amenable to study. BALENTL 4 and 14 gave significant suppression of the MLR between BALB/c and C57BL/6; BALENTL 14 also inhibited the generation of BALB/c effector cells against C57BL/6 spleen cells. None of these T cell lines had any effect on the proliferative response of BALB/c spleen cells induced by concanavalin A. However, there was approximately 50% suppression of the phytohemagglutinin response of BALB/c spleen cells by BALENTL 14.

Characteristics of BALB/C T cell lymphomas grown as continuous in vitro lines

Transplanted lymphomas (Thy 1.2+, Ig-) of BALB/c mice, induced by the injection of 1-ethyl-1-nitrosourea, were adapted for growth as in vitro lines to provide potential tools for investigation of T lymphocyte differentiation and functions. All these tissue culture lines maintained the same pattern of surface differentiation antigens (Ly, TL, and Thy-1 antigens) as they had expressed during in vivo passages: BALENTL 13 was Thy 1.2+, TL.2-, and Ly 1+2-. BALENTL 3, 4, 5, 6, 7, 8, and 14 were Thy 1.2+, TL.2+, and Ly 1-2+. P1798 and BALENTL 9 were Thy 1.2+, TL.2+, and Ly 1-2+. There were various levels of terminal transferase activity present among these T cell tumor lines. The range of variation was from 4.6 units/10(8) cells to 29.3 units/10(8) cells (normal thymocytes, 5.0 units/10(8) cells). This 6-fold variation in TdT activity was present even among those cell lines which were Ly 1-2+, TL+. Most cultures lines had chromosome numbers near 40 and generation times of 11 to 22 hr. There were no significant morphologic changes after the adaptation of these tumors in culture except an increase in cytoplasmic C-type virus particles.