Thromboplastic and fibrinolytic activities in various organs of congenitally athymic nude mice.

Thromboplastic and fibrinolytic activities in various organs of congenitally athymic nude mice were estimated. These activities varied from one organ to another and the organs were divided into six groups of possible combinations of these activities. The lung revealed high thromboplastic and high fibrinolytic activities, while the liver showed low thromboplastic and low fibrinolytic activities. The pattern of distribution of these activities in various organs of nude mice was almost similar to that of rats and mice with normal thymus. No plasmin activity was found in all organs.     

Frequencies of background cytoplasmic Ig-containing cells in various lymphoid organs of athymic and euthymic mice as a function of age and immune status

The distribution of background Ig-secreting cells, measured as cells containing cytoplasmic immunoglobulin (C-Ig cells), over spleen, bone marrow, lymph nodes and Peyer's patches was studied in congenitally athymic (nude) mice and heterozygous euthymic mice as a function of age and immune status (germ-free (GF) vs specific pathogen-free (SPF]. In young athymic as well as in young euthymic mice, the spleen was found to contain the great part of all C-Ig cells, irrespective of whether the mice were GF or SPF. The number of C-Ig cells in the spleen was found to be rather constant over the life span, while the number of C-Ig cells in the bone marrow of all groups of mice greatly increased with age. This indicates that the relative shift of C-Ig cells to the bone marrow is neither dependent on the presence of the thymus, nor on the microbiological status of the mice. However, at young and intermediate age the microbiological status of the mice did affect the total number of C-Ig cells per mouse. This was mainly due to the effect upon the bone marrow, mesenteric lymph nodes and Peyer's patches. At these ages the background Ig synthesis in these organs appeared to be mainly dependent on external antigenic stimulation, in contrast to the spleen, where the Ig synthesis appeared to be mainly due to endogenous stimulation. The Ig (sub)class distribution of the C-Ig cells was different for all different organs tested. Hardly or no difference in percentage distribution was found between the GF nude and GF heterozygous mice. Most C-Ig cells in spleen, bone marrow and lymph nodes of the GF mice were of the IgM isotype. C-IgG and C-IgA cells occurred in substantial percentages only in bone marrow and lymph nodes. In the lymph nodes of GF nude mice a remarkably high percentage of C-IgA cells was found.     

Persistent Cryptosporidium infection in congenitally athymic (nude) mice.

Nude (nu/nu) BALB/c mice and their white (nu/+) littermates were experimentally infected with Cryptosporidium sp. at 6 days of age. In white mice, the infection was transient, but in nude mice a persistent infection developed that was characterized by diarrhea and, occasionally, death. There were villus atrophy and crypt hyperplasia in the small intestine of infected nude and white mice necropsied at 11 days of age. Persistently infected nude mice had, in addition to the above small intestinal lesions, diffuse cystic mucosal hyperplasia and crypt abscesses in the large intestine at 56 days of age. These results suggest that T cells are required for recovery from the Cryptosporidium infection but are not required for epithelial cell loss in cryptosporidiosis. Both nude and white mice appeared to be relatively more resistant to Cryptosporidium infection at 42 days of age than at 6 days of age.     

Susceptibility of congenitally athymic (nude) mice to sporotrichosis

Congenitally athymic (nu/nu) mice were found to be more susceptible to intravenous challenge with Sporothrix schenckii than their phenotypically normal (nu/+) littermates as measured by lethality and the number of viable yeast cells in the liver 7 days postinfection. Thymus reconstitution of nu/nu mice (nu/thy) conferred a significant degree of resistance to sporotrichosis. Immunization greatly enhanced the resistance of nu/thy and nu/+ mice, but unexpectedly increased the susceptibility of nu/nu mice. The susceptibility of nonimmunized nu/nu mice and the finding that thymus transplants augmented resistance to sporotrichosis suggest that T lymphocytes are critical to host defense.     

Comparative patterns of serum immunoglobulin levels in specific-pathogen-free congenitally athymic (nude), hereditarily asplenic (Dh/+), congenitally athymic-asplenic (lasat) and splenectomized athymic mice.

Serial determinations of serum immunoglobulin levels were assessed in congenitally athymic (nude), hereditarily asplenic (Dh/+) and congenitally athymic-asplenic (lasat) mice and the results compared to normal intact littermate controls (nu/+), neonatally splenectomized nu/+ and neonatally splenectomized nude mice. Quantification of Ig levels was accomplished by radial immunodiffusion, for IgM, IgG1, IgG2a, IgG2b and IgA antibody isotypes. Intact spleen and/or thymus function was shown to have marked effects on the age-dependent development of serum IgM, IgG2b and IgA production. Furthermore, because of higher levels of IgA in congenitally athymic-asplenic mice and neonatally splenectomized nude mice v. sham splenectomized nude mice, it is suggested that an IgA-specific suppressor population resides in the spleen. Finally, because of frequent problems in the literature in interpretation of immunoglobulin values, the criteria for the statistical evaluation of such data in establishing normal serum Ig values and ascertaining real differences between treatment groups are emphasized.     

Frequencies of background cytoplasmic Ig-containing cells in various lymphoid organs of athymic asplenic (lasat), athymic,asplenic and normal BALB/c mice

The frequency of immunoglobulin-containing plasma blasts and plasma cells (C-Ig cells) was determined by means of immunofluorescence in various lymphoid organs of hereditarily athymic asplenic (lasat), athymic (nude), asplenic (all on a BALB/c background) and normal BALB/c mice. Two age groups were tested, namely 8 and 14 weeks.The total number of C-Ig cells in spleen, bone marrow, lymph nodes and Peyer''s patches together was the largest in the normal BALB/c mice, the smallest in the lasat mice, and intermediate in the athymic mice and the asplenic mice. The mice of all four groups had more C-Ig cells at the age of 14 weeks than at the age of 8 weeks. In 8-week-old BALB/c mice and in athymic nude mice most C-Ig cells were located in the spleen. In lasat mice and in thymus-bearing asplenic mice the bone marrow was the major site of localization of C-Ig cells. In all four groups of mice the number of C-Ig cells increased considerably with age, especially in the bone marrow. In athymic mice, whether asplenic or not, C-Ig cell numbers in the Peyer''s patches were deficient.The percentage distribution of C-IgM, C-IgG1, C-IgG2, C-IgG3 and C-IgA cells was different for different lymphoid organs, and was dependent on both the spleen and the thymus. In normal BALB/c mice C-IgM cells were the most frequent in the spleen, whereas the other classes of C-Ig cells were the most frequent in the other lymphoid organs. In absolute numbers, C-IgM cells were the most numerous in the two groups of eusplenic mice, and C-IgG and C-IgA cells in the two groups of euthymic mice.     

Thymic-dependent anti-hapten response in congenitally athymic (nude) mice immunized with DNP-thymosin.

Immunization of congenitally athymic (nu/nu) and adult thymectomized, irradiated bone marrow, reconstituted (TxBm) mice with DNP5-thymosin (dinitrophenylated-bovine thymosin fraction 5) was found to elcit IgM and IgG anti-DNP plaque-forming cells in these animals. Further studies indicated that this response was antigen specific and not due to polyclonal activation. Since the hormonal properties of the thymosin were retained following linkage with hapten and DNP-thymosin was immunogenic in CBA/N and CBA/N female X DBA/2 male)F1 male mice, animals previously shown to have an X-linked inability to respond to thymus-independent antigens, it was concluded that DNP-thymosin functions both as a hormone and as a T-dependent antigen in eliciting an immune response in nu/nu and TxBm mice. Additional support for this conclusion was provided by the demonstration that DNP-thymosin could specifically prime for and elicit an anamnestic response in nu/nu mice. These results indicate that further investigation of the immune activities of DNP-thymosin may provide valuable insight in characterizing the maturation of helper T cells and their subsequent interaction with B cells.     

Phospholipase B activity in congenitally athymic (nude) mice infected withTrichinella spiralis

The effects of an infection with 200Trichinella spiralis larvae on the intestinal phospholipase B activity and bone marrow eosinophilia of congenitally athymic (nude) mice (BALB/c; NU/NU) were studied. Nude mice were used since it had been shown that they do not undergo a typical worm expulsion and also they lack a thymus. The results showed that nude mice do not develop either an increased bone marrow eosinophilia or an elevation in intestinal phospholipase B activity. The findings thus support the hypothesis that phospholipase B is involved in the expulsion of parasitic worms and that elevated enzyme levels and expulsion are thymus cell dependent.     

Nocardia infections in congenitally athymic (nude) mice and in other inbred mouse strains.

The mortality rate and histopathological features of Nocardia asteroides and Nocardia brasiliensis infections in congenitally athymic (nude) mice of ICR and C3H/eB origins were quite different from what we found for Swiss white mice and other inbred mouse strains (namely, C57/BL/6J, New Zealand Black, BALB/c, CBA/LAC, and C3H/eB). The immunocompetent littermates of the congenitally athymic mice occupied an intermediate position between their athymic siblings and Swiss white mice in terms of their responses to both these organisms. Macrophage ingestion and destruction of N. brasiliensis, as demonstrated by electron microscopy, was found to occur. The T-lymphocyte appears to be an essential component in normal mouse resistance to infection by both N. asteroides and N. brasiliensis.     

Kinetics of recovery of serum Ig levels and of cytoplasmic Ig positive cells in various lymphoid organs of nude mice after thymus transplantation.

The long-term effects of thymus transplantation in nude mice were studied with regard to the number of cytoplasmic immunoglobulin positive plasmablasts and plasma cells (C-Ig cells) in various lymphoid organ and their immunoglobulin (Ig) class distribution profile. These data were correlated with the serum Ig levels of the same mice. Four weeks after thymus transplantation, the number of C-Ig cells in the spleen of nude mice had increased two- to three-fold over that found in normal nude mice and normal heterozygous littermates of the same age. This overshoot subsided at 8 weeks after thymus transplantation. The increase of the C-Ig cell number in the other lymphoid organs tested (bone marrow, mesenteric lymph nodes and Peyer''s patches) started later than in spleen, and did not show a clear overshoot. Almost complete recovery of the C-Ig cell pattern to that of normal littermates was found 32 weeks post-transplantation. Analysis of the Ig class distribution of the C-Ig cells showed that the increase of the C-Ig cell numbers after thymus transplantation in nude mice was almost exclusively confined to IgG1, IgG2 and IgA. The increase of C-IgG1 and C-IgG2 cells in spleen and bone marrow correlated with a simultaneous increase of the serum IgG1 and IgG2 levels, suggesting that these organs are the major source of serum IgG in young adult mice.     

Thymus dependency of induced immune responses against Hymenolepis nana (cestode) using congenitally athymic nude mice.

Anti-parasite antibody responses were compared among several strains of mice experimentally infected with the dwarf tapeworm, Hymenolepis nana. The antibody titres were highly variable among the mouse strains in addition to variation in worm fecundity and longevity. The influence of the thymus on both infection and anti-parasite antibody production (especially of IgE isotype) was studied by the use of congenitally athymic (nu/nu) nude and their phenotypically normal (nu/+) CD-1(ICR) mice infected with H. nana. All nude (nu/nu) mice harboured fully mature 70 day old adult tapeworms of the first generation derived from eggs initially given on day 0. In addition, they contained (a) younger second generation adults derived from autoinfection and present in the intestinal lumen, (b) a number of abnormally large (about 1-2 mm in diameter) balloon like, fluid filled cysticercoids in not only the intestinal tissue but also parenteral tissues such as the mesenteric lymph nodes, liver and lung, and (c) normal cysticercoids derived from challenging eggs in the intestinal tissue. Infected nude mice produced no antibodies detectable by PCA (IgE) and double diffusion (IgG) tests. In contrast, normal (nu/+) mice and nude mice reconstituted with thymocytes expelled almost all luminal adults of the primary infection by day 70 and produced antibodies to extracts of adult H. nana. Neither autoinfection nor reinfection following egg challenge occurred in any of these normal (nu/+) and reconstituted nude mice. Therefore, acquired immune responses against H. nana (as assessed by resistance not only to the tissue phase measured by the failure of tissue cysticercoid recovery from egg challenge, but also to the lumen phase assessed by the failure of autoinfection adult recovery and 'worm expulsion' of the initially established adults) are all thymus-dependent in mice. The antibody responses examined are also thymus-dependent.     

Herpetic keratitis in athymic (nude) mice.

The inflammatory response to herpes simplex virus infection of the cornea was studied in athymic nude (nu/nu) and heterozygote (nu/+) BALB/c mice. Although athymic mice were highly susceptible to HSV infection and died 13 to 17 days after corneal inoculation, they failed to develop necrotizing keratitis of the cornea. Heterozygote mice survived the initial virual infection, but many of these mice developed necrotizing keratitis and permanent corneal scarring. Light and electron microscopy showed numerous inflammatory cells (polymorphonuclear leukocytes and lymphocytes) in the corneas of heterozygote mice, but not in the athymic mice. These studies suggest that the immune system plays a dual role in herpes simplex virus infection of the cornea: protection against dissemination of the virus and immunopathogenesis of necrotizing keratitis in the cornea.     

Hymenolepis diminuta infections in congenitally athymic (nude) mice: worm kinetics and intestinal histopathology

Serial bleedings were obtained from two mules during prolonged immunization, one with type XXV the other with type VIII pneumococcal vaccine. IgGa, IgGb, IgGc, IgB, IgG(T) and IgM present among purified Pn anti-XXV and Pn anti-VIII immunoglobulin isolated from various bleedings were identified by use of rabbit anti-equine heavy chain specific reagents. Radioimmunodiffusion with 14C-labelled type XXV pneumococcal capsular polysaccharide and horse and donkey reagents with species specificity directed against donkey or horse IgGa respectively, demonstrated both parental horse and donkey IgGa heavy chain isotypes among the anti-PnXXV antibodies of the interspecies hybrid. Qualtitative and quantitative examination of the cross-precipitation of mule anti-PnXXV sera with the capsular polysaccharides of pneumococcal types IV, X and XA, with birch sap, ketha gum, and with polysaccharides of E. coli, Klebsiella and Rhizobium was carried out and compared with data obtained with anti-PnXXV raised in a horse. Analysis of supernatants from the cross-reactions showed that distinct subfractions had reacted. indicating a marked heterogeneity of the antibodies.     

Distribution of various immunoglobulin containing cells in canine lymphoid tissue

The spleen, lymph nodes and gastro-intestinal mucosae of the dog were investigated with respect to the size and nature of their plasma cell populations. As in all other mammals so far studied, the gastro-intestinal mucosae of the dog were conspicuous by their wealth of IgA-containing plasma cells.     

Thymus dependence and independence of intestinal pathology in a Trichinella spiralis infection: a study in congenitally athymic (nude) mice.

The hypothesis that non-specific histopathological gut changes are thymus-dependent was tested in a helminth infection--the nematode Trichinella spiralis. The study was performed in congenitally athymic (nu/nu) mice and their thymus-bearing heterozygous litter-mates (+/mu). The non-specific histopathological changes of the small intestine were judged on villus/crypt ratio and mitotic index; for the specific (= immunological) reaction the number of pyroninophilic cells in the small intestine was used as criterion. T. spiralis induced non-specific histopathological reactions both in nu/nu and +/nu mice, whereas the number of pyroninophilic cells was only increased in +/nu mice. It was concluded that the immunological reaction was dependent on the immune status of the host, whereas the non-specific histopathological changes were not, i.e. they were thymus-independent.     

Virus carrier state suppresses tumorigenicity of tumor cells in athymic (nude) mice.

Nude mice injected subcutaneously with normal uninfected BHK 21 cells or HeLa cells regularly develop large, rapidly-growing tumours at the subcutaneous site of inoculation. However, these same tumour cell lines when persistently infected with VSV or other enveloped RNA viruses are either rejected or form small nodules in nude mice. This rejection phenomenon probably involves some type of immunocyte since heavily-irradiated nude mice (500 rads) cannot reject persistently infected cells but develop large, rapidly-growing tumours which shed virus and defective interfering virus (DI) and which do not exhibit the lymphocytic infiltration observed in the nodules of unirradiated mice given persistently infected cells. Finally, it was possible to select a subline of BHK 21-VSV carrier cells which regularly produces large rapidly-growing tumours in normal unirradiated nude mice, although all these carrier cells express virus antigen and shed large amounts of mature infectious virus and DI both in vivo and in vitro.     

Hexamita and Giardia as a cause of mortality in congenitally thymus-less (nude) mice

Two intestinal flagellates, Hexamita muris and Giardia muris, were found in high concentrations in most of the congenitally thymus-less (nude) mice in a conventional colony being maintained at the Radiobiological Institute TNO.

Antiflagellate therapy markedly reduced mortality, with >50% of the mice living to 110 days. In mice receiving thymus transplants but no antiflagellate treatment the mortality rate was less than in either control or treated mice. In addition, histopathological examination of mice with thymus transplants revealed fewer intestinal flagellates than in control mice.

It is suggested that the wasting syndrome seen in nude and neonatally thymectomized mice may be aggravated by infestation with Hexamita and Giardia.

     

Infectious agents in immunodeficient murine models: pathogenicity of Actinomyces israelii serotype I in congenitally athymic (nude) mice.

Shortly after intranasal infection of guinea pigs with Mycoplasma pneumoniae, the titers of the complement components increased significantly in bronchial secretions by the folllowing amounts, compared with the titer of a control group: C1, about 2-fold; C2, 1.6-fold; C3, 17-fold; and C4, 942-fold. Histopathological signs of inflammation were not apparent at this time. At 2 weeks after infection, when the titers of complement components in the bronchial secretions were at the level of control values or lower, the serum antibody titer increased, and it reached the highest level at 6 weeks after infection. Therefore, one can distinguish two phases of reaction of the macroorganism to intranasal inoculation. The increase in complement components shortly after infection may represent an earlyunspecific defense mechanism of the host before the specific immune response becomes effective, since the complement system can be activated by M. pneumoniae via the classical as well as the alternative pathway in the absence of antibodies.