Norman D. Reed

Long-Term Maintenance of Normal Human Skin on Congenitally Athymic (Nude) Mice

Summary Congenitally athymic (nude) mice have been shown to accept for their lifetime full thickness, normal human skin grafts without immunosuppressive therapy. The biological and medical significance of the long-term maintenance of human tissues in nonhuman subjects is discussed.

Immune Response Potential of Mast Cell-Deficient W/Wv Mice

Immune responses of mast cell-deficient WBB6F1-W/Wv mice and their mast cell-sufficient littermates (LM: WBB6F1-W/+, Wv/+ and +/+) were compared. After a single intravenous injection of sheep erythrocytes (SE), polyvinylpyrrolidone or bacterial lipopolysaccharide, the antigen-specific IgM plaque-forming cell (PFC) response of W/Wv mice was similar to or greater than the response of LM mice. When both primary and secondary injections of SE or chicken gamma-globulin were given to mice and antigen-specific IgG PFC responses quantified, the response of W/Wv again was similar to or greater than that of LM mice. Serum titers of antigen-specific IgE were higher in W/Wv than in LM mice after injections of ovalbumin in alum or infections of Nippostrongylus brasiliensis. Ovalbumin-sensitized W/Wv and LM mice developed active systemic anaphylaxis after ovalbumin challenge. The ability of W/Wv mice to be sensitized for and elicit contact sensitivity (CS) reactions was studied using picryl chloride or dinitrofluorobenzene as sensitizing and challenge agents and quantifying 24-hour reactions by change in ear thickness. SE or methylated bovine serum albumin was used to sensitize and challenge mice for delayed-type hypersensitivity (DTH) reactions which were quantified at 24 h by change in foot pad or ear thickness. CS and DTH reactions of W/Wv and LM mice were similar. No evidence of immune deficiency of W/Wv mice was found.

The Course of Hymenolepis nana Infections in Thymus-Deficient Mice

The kinetics of infection with Hymenolepis nana was examined in normal thymus-deficient mice. Following inoculation with 5 cyticercoids, the number of adult lumen-dwelling H. nana in congenitally thymus-deficient (nude) mice ultimately was at least 75 times the maximum infection intensity of normal thymus-bearing mice or thymus-reconstituted nude mice. Similar results were obtained following inoculation of H. nana eggs into nude mice; although thymus-bearing mice eliminated their infections, nude mice harbored more than 1,000 adult worms throughout the 7 weeks of the experiments. These data show that in mice, immunity is not generated against H. nana in the absence of thymus function. The data also confirm and establish the requirement of cysticercoid development in the intestinal mucosa for stimulation of a protective immune response against H. nana.

The immune response of congenitally athymic (nude) mice to the intestinal nematode Nippostrongylus brasiliensis.

Summary Phenotypically normal mice expelled the intestinal nematode Nippostrongylus brasiliensis by Day 10-12 post-larval-inoculation. Congenitally athymic (nude) mice maintained, for their lifetime, infections of this parasite. The worm expulsion mechanism was generated by nude mice which had been given thymus gland implants 30 days prior to larval inoculations. The nude mouse may prove most useful in studies on mechanisms of immunity to helminthic infections.

Bone marrow origin of mucosal mast cells

Infection with the intestinal parasite Nippostrongylus brasiliensis stimulates an accumulation of mucosal mast cells (MMC) in the villi of the small intestine of normal but not athymic or W/Wv anemic mice. W/Wv mice are congenitally deficient in both MMC and skin and connective tissue mast cells (CTMC). Athymic mice have normal or elevated numbers of CTMC but are severely deficient in MMC. CTMC derive from the bone marrow. To determine the origin of MMC, athymic and W/Wv mice were given various hematopoietic or lymphoid tissues from normal littermate or beige mice and the MMC response to N. brasiliensis infection was evaluated. The MMC defect in athymic mice was repaired by grafts of thymus cells, thymus gland, or spleen cells, but not by bone marrow cells or anti-Thy 1-treated bone marrow or spleen cells. The MMC and CTMC defects of W/Wv mice were repaired by grafts of bone marrow, spleen cells, or anti-Thy 1-treated bone marrow or spleen cells. Neither the MMC nor the CTMC defect in W/Wv mice was repaired by grafts of thymus cells or thymus glands. These results indicate the following, MMC, like CTMC, derive from the bone marrow and not from the thymus. MMC require a thymic influence for development. Athymic mice possess bone marrow precursors for both MMC and CTMC but lack a thymus-dependent component necessary for MMC development. W/Wv mice lack both MMC and CTMC mast cell precursors but possess the thymus-dependent component required for MMC development.

Regulation of the immune response to polyvinylpyrrolidone:effect of antilymphocyte serum on the response of normal and nude mice.

Abstract The plaque-forming cell (PFC) responses of normal and congenitally thymus-deficient (nude) mice to polyvinylpyrrolidone (PVP) were compared. Normal and nude mice responded similarly to an optimally immunogenic dose of PVP. Antithymocyte serum or antilymphocyte serum treatment of immunized mice caused a five to 10-fold increase in the PVP-specific PFC response in normal mice; the response in nude mice was not increased by such treatment. The data suggest that, although thymus-derived cells are not an absolute requirement in the immune response to PVP, these cells can regulate the magnitude of the immune response to this antigen.

Reconstitution of the in vitro immune response of congenitally thymusless (nude) mice.

Summary Spleen cell cultures from congenitally thymusless (nude) mice were found to be unresponsive to SE in vitro. The addition of 5.0 × 107 thymus cells from Balb/c or littermate animals to “nude” spleen cell cultures enabled these cultures to respond to SE. An in vitro response to SE could also be obtained by addition of normal spleen cells from Balb/c mice. As few as 2.4 × 105 Balb/c spleen cells established an immune response in nude spleen cell cultures. The reconstitution of nude spleen cell cultures with thymus cells indicates that while a deficiency of thymus-derived cells exists in nude mice, they have functional bone marrow-derived cells. We thank R. W. Dutton for instructing one of us (D.P.A.) in the use of the Mishell-Dutton Procedure, and R. C. Roberts and D. S. Falconer for providing the breeding nucleus of mice carrying nude.

The requirement of thymus competence for both humoral and cell-mediated steps in expulsion of Nippostorngylus brasiliensis from mice.

The worm damaging process (step 1 of Nippostrongylus brasiliensis expulsion from rodents) does not occur in congenitally thymus-deficient (nude) mice as determined by worm morphology, female worm fecundity, and kinetics of worm expulsion upon transfer into normal rats. Expulsion of damaged N. brasiliensis (step 2) does not occur subsequent to transfer of such worms from rats into nude mice. Morphological changes and reduced fecundity appeared in adult worms from normal thymus-bearing mice as early as the first day of patency (day 6 of infection). Thus, the worm damaging process is initiated several days earlier in mice than in rats and may, therefore, account for the reduced longevity of N. brasiliensis in mice compared with rats.

Immune Response of Congenitally Thymusless Mice to Heterologous Erythrocytes

Summary Hemagglutinin and hemolysin production by congenitally thymusless (“nude”) mice in response to intraperitoneal injection of 107, 108, 109, or 1010 sheep erythrocytes (SE) was significantly lower than in normal littermate controls. The plaque-forming cell response of nudes was also impaired. Rosette-forming cells (RFC) were observed in unimmunized nude mice. Injection of SE did not result in the formation of increased numbers of RFC in nude mice, whereas littermate controls responded strongly. The authors express appreciation to R. C. Roberts and D. S. Falconer for providing the breeding nucleus of mice carrying nude and to Mrs. Billie Welty for excellent technical assistance.

In Vitro Immune Response to Lipopolysaccharide: Thymus-Derived Cells not Required

An in vitro immune response to lipopolysaccharide was obtained using heat-killed Escherichia coli cells as antigen. Spleen cell cultures from phenotypically normal mice responded to sheep erythrocytes and to lipopolysaccharide. Spleen cell cultures from congenitally athymic (nude) mice failed to respond to sheep erythrocytes but did respond to lipopolysaccharide. These results suggest that the in vitro immune response to lipopolysaccharide does not require the participation of thymus-derived cells.