Chemical properties of antigen-dependent migration inhibition factor in mice.

Antigen-dependent migration inhibition factor produced in cultures of mouse lymph node lymphocytes was further characterized. It was found to bind to Concanavalin A and could be eluted by the appropriate sugar. The pI of the activity was found to be between 6-4 and 6-5 by isoelectric focusing.     

Experimental Cryptosporidium parvum infections in immunosuppressed adult mice.

Five strains of adult mice were immunosuppressed with the synthetic glucocorticosteroid dexamethasone (DEX), administered either orally or intraperitoneally. The strains of mice used were C57BL/6N, DBA/2N, CBA, C3H/HeN, and BALB/cAnN. All mice were evaluated for susceptibility to Cryptosporidium parvum after intragastric inoculation with 10(6) oocysts per mouse. The DBA/2N, CBA, C3H/HeN, and BALB/cAnN mice given 0.25 micrograms of DEX per g per day orally (the dose and route previously used to infect rats with C. parvum) failed to develop chronic infections. However, the C57BL/6N mice sustained light infections during the entire 28-day experiment. The five strains of mice were also administered DEX intraperitoneally at concentrations ranging from 62.5 to 500 micrograms/day. Only the C57BL/6N mice given DEX at 125 micrograms/day developed chronic infections which persisted over 10 weeks, suggesting that the genetic background of the mouse plays a role in determining susceptibility to cryptosporidosis following immunosuppression with DEX. We believe that the C57BL/6N mouse model will prove to be superior to other animal models for evaluating potential anticryptosporidial agents, as well as for elucidating the immunological defects that allow C. parvum to establish chronic infections, because of cost effectiveness and ease in maintenance, breeding, and handling. We also evaluated the C3H/HeJ/beige mouse (lacks natural killer cell activity) and the C57BL/6N mouse maintained on a low-protein diet to induce immunosuppression. Neither of these mice exhibited heavy cryptosporidial infections.     

Effects of the Chinese medicine matrine on experimental C. parvum infection in BALB/c mice and MDBK cells

To date, there are no effective methods of treating Cryptosporidium infection in animals or humans. Matrine, a main active alkaloid extract from Sophora flavescens, has potential antineoplastic, antifibrotic, anti-inflammatory, and antitumor activities. However, the treating effects of matrine on Cryptosporidium infection as well as its mechanisms of action are largely unknown. The present study investigated the effects of matrine on Cryptosporidium parvum infection in both in vitro and in vivo models. Oocyst excretion, plasma D-lactic acid concentrations, and bacterial translocation rates were assayed to evaluate the efficacy of treatment in experimentally infected BALB/c mice. Matrine effects on parasite replication and lactate dehydrogenase (LDH) activity were assessed in cell cultures. The results showed that matrine could significantly reduce the number of C. parvum oocysts by 54-63?%, and the number of C. parvum-infected cells by 28-58?%. Plasma D-lactic acid concentrations and LDH activity in the matrine-treated groups were lower than the infected group (P??0.05). These results clearly demonstrate that matrine can inhibit C. parvum infection. Integrity of cell membranes and of the mucosal barrier is improved in treated animals as compared to untreated infected controls. Thus, it is concluded that matrine has a potential in therapeutic applications against C. parvum infection.     

Mycobacterium resembling Mycobacterium fortuitum that produces brown pigment.

Two cultures of acid-fast bacilli with characteristics most closely resembling those of Mycobacterium fortuitum were recovered as casual isolates from sputa of a patient with an apparent brochogenic tumor. One of the cultures was consistenly cream colored to rosy buff. The other, however, changed from buff to rust to dark brown and had the gross appearance of a fungus culture.     

BCG, in contrast to C. parvum, does not induce increased sensitivity to the toxic effects of indomethacin in mice

Treatment of mice with killed Corynebacterium parvum (also designated Propionibacterium acnes, P. acnes) or Bacille Calmette Guerin (BCG) leads to modification of several of the same host systems. However, BCG, in contrast to C. parvum, did not induce increased sensitivity to the toxic effects of indomethacin in BALB/c or C57B1/6 mice. In addition, treatment of mice with BCG did not interfere with the induction of sensitivity by C. parvum. Therefore C. parvum must uniquely induce changes in host systems which alter the sensitivity to this anti-inflammatory drug. Additional experiments with splenectomized animals revealed that the presence of this organ, which undergoes hypertrophy following C. parvum treatment, was not necessary for the induction of indomethacin sensitivity. Presentation of C. parvum via the subcutaneous route versus the intraperitoneal route revealed that the two routes were equally efficient in inducing sensitivity in C57B1/6 mice but the former route was less effective (50% deaths) than the intraperitoneal route (95% deaths) in BALB/c mice. These results indicate that host related factors (genetic) may be important in the generation of enhanced sensitivity to the toxic effects of indomethacin.     

Immunosuppression and splenomegaly in Entamoeba histolytica infection in mice

Intestinal amoebiasis caused by Entamoeba histolytica trophozoites in mice is accompanied by a depression in the ability of this host to develop an immune response to sheep red blood cells. The number of splenic plaque-forming cells was reduced in mice inoculated intracecally with 2.5 x 10(5) trophozoites at 15, 25, 40, 65 and 75 days after infection when compared with non-infected mice. It was found that there was no significant difference between the spleen weight of the infected and non-infected control animals at 5 and 10 days following infection. However, a significant increase in spleen weight was observed by 15 days of infection and the spleens remained enlarged until termination of the experiment at 75 days. Thus, there was an inverse correlation between the PFC response and the spleen weight of infected animals.     

Basic principle of the lifespan in the nematode C. elegans

We present a biophysical model based on the principles of fluctuation and regulation to explain the effect of stochastics on survival. The model is a good fit for the survivorship and mortality rates observed in the nematode Caenorhabditis elegans. A parameter included in the theory, which is called the fluctuation constant, correlates well with a change (or declining rate) of respiration with age, which we term the physiological decline rate. The square of the physiological decline rate is proportional to the reciprocal of the fluctuation constant as revealed in a diffusion equation. In addition, the maximum and mean life spans are proportional to the reciprocal of the decline rate. The framework involved in the fluctuation theory is compatible with the existence of a regulatory system such as that acting in the insulin/insulin-like growth factor-1 (IGF-1) signaling pathway during adulthood, and that sensing, switching, and memorizing the rate of mitochondrial respiration early in life.     

Protection of mice against mouse hepatitis virus by Corynebacterium parvum.

C57BL/6 mice that are highly susceptible to infection with mouse hepatitis virus type 3 were protected against intraperitoneal viral infection by simultaneous intraperitoneal injection of Corynebacterium parvum. No protection was observed when C. parvum was given intravenously or when it was injected intraperitoneally 3 days before viral infection. Protective effects were, however, consistently found when C. parvum was given 2 h before or 2 h after viral infection. Activity was seen only against 10 50% lethal doses and not against 100 50% lethal doses. C. parvum also caused a significant decrease of virus type 3. These data suggest a direct effect of C. parvum on virus-susceptible cells. Injection of C. parvum in mice caused activation of natural killer (NK) cells and of interferon production. However, these two effects were equally demonstrable at high and low doses of C. parvum, whereas protection against mouse hepatitis virus type 3 was not demonstrable at low doses of C. parvum. Thus, antiviral protection may be dissociated from activation of NK cells and induction of interferon.     

Lymphoproliferative and Cytokine Responses to Cryptosporidium parvum in Patients Coinfected with C. parvum and Human Immunodeficiency Virus

We compared the lymphoproliferative and cytokine responses to Cryptosporidium parvum in human immunodeficiency virus (HIV)-seropositive and -seronegative patients. The lymphoproliferative and cytokine responses (interleukin-2 [IL-2], IL-4, IL-5, IL-10, gamma interferon, and tumor necrosis factor alpha) were assessed for 11 HIV-seropositive, Cryptosporidium-positive (group I) patients; 20 HIV-seropositive, Cryptosporidium-negative (group II) patients; 10 HIV-seronegative, Cryptosporidium-positive (group III) patients, including four post-renal transplant (group IIIa) and 6 presumably immunocompetent (group IIIb) patients; and 20 HIV-seronegative, Cryptosporidium-negative healthy individuals (group IV). No significant difference was observed in the number of patients showing positive lymphoproliferative responses in group I compared to group III (post-renal transplant [group IIIa] or immunocompetent [group IIIb]) patients, while a comparison of the median stimulation indices shows that responses were significantly lower in Cryptosporidium-infected, immunosuppressed (group I and IIIa) patients than in immunocompetent (group IIIb) patients. The number of patients showing positive responses and median stimulation indices was significantly higher for Cryptosporidium-infected (HIV-seropositive and -seronegative) individuals than for uninfected individuals, suggesting that Cryptosporidium induces significant in vitro lymphoproliferative responses in infected individuals. Cytokine levels, except for that of IL-5, were significantly higher in Cryptosporidium-infected (groups I and III) individuals than in uninfected (groups II and IV) individuals. There was no significant difference between the group I and III patients and between Cryptosporidium-infected immunosuppressed (group I or IIIa) and immunocompetent (group IIIb) patients.     

Protection against herpes simplex virus infection in mice by Corynebacterium parvum.

Corynebacterium parvum administered in mice prior to herpes simplex virus (HSV) infection significantly protected them against lethal encephalitis. This was seen both with a mouse strain highly susceptible to HSV and with one relatively resistant to HSV. Mice immunosuppressed by cyclophosphamide and showing an increased mortality after HSV infection were also protected by C. parvum pretreatment. However, C. parvum given simultaneously with or after HSV infection did not exert a therapeutic effect.     

Susceptibility of germfree or antibiotic-treated adult mice to Cryptosporidium parvum.

Adult mice are more resistant than neonatal mice to intestinal colonization with the protozoan parasite Cryptosporidium parvum. Development of a mature intestinal flora may play a role in this resistance. We compared susceptibilities to colonization with C. parvum in adult conventional mice, adult germfree mice, and adult conventional mice treated with oral antibiotics to deplete the intestinal flora. Germfree mice of both CD1 and BALB/c strains were colonized at day 7 following inoculation with C. parvum oocysts isolated from the feces of an infected, diarrheic calf. Age-matched conventional mice of the same strains were comparatively resistant to colonization. Conventional mice treated with antibiotics remained resistant to colonization. These results suggest that the microflora in the intestine was not the sole determinant of resistance or susceptibility to colonization. The germfree adult mouse as an experimental model of cryptosporidiosis is discussed.     

Monoclonal antibody immunotherapy in nude mice persistently infected with Cryptosporidium parvum.

Three groups of congenitally athymic nude mice were persistently infected following oral administration of 2 x 10(7) Cryptosporidium parvum oocysts. Two groups were treated once daily for 10 days with either neutralizing monoclonal antibody (MAb) 17.41 or an isotype control MAb. The third group received no treatment. Intestinal-infection scores were significantly decreased in nude mice treated with MAb 17.41 compared with isotype control MAb-treated and nontreated control groups (P less than 0.005). Biliary and pancreatic cryptosporidial-infection scores were similar for the MAb 17.41-treated and isotype control MAb-treated groups (P greater than 0.05).     

Oral immunization of mice with a live recombinant Yersinia enterocolitica O:9 strain that produces the cholera toxin B subunit.

The 70-kilobase pYV plasmid of Yersinia enterocolitica encodes a set of proteins called Yops that are produced during infection. To use Y. enterocolitica as a live carrier to present the cholera toxin B (CT-B) subunit to the immune system, we constructed an operon fusion between ctxB and the yop51 gene. This operon fusion was either cloned on an RSF1010-derived plasmid or integrated into the pYV plasmid itself. In Y. enterocolitica, both constructions directed the synthesis of free CT-B only under conditions of Yops production, i.e., at 37 degrees C in a medium deprived of Ca2+. Bacteria containing both types of recombinant plasmids were given orally to mice. A serum antibody response against CT-B was detected in both cases. A secretory immunoglobulin A activity specific to CT-B was also observed in the intestinal secretions. According to immunoblot analysis, the serum antibody response was only directed against the polymeric form of the B subunit. The ctxB gene was also inserted in frame within yop51, giving a chimeric Yop51-CT-B protein that was secreted into the surrounding medium. In this case, however, no antibody response was observed after oral inoculation of mice. This lack of response probably results from the inability of the hybrid protein to assemble into the polymeric form of the B subunit.     

Induction of splenomegaly in mice by killed Coxiella burnetii cells

Splenomegaly induced in mice inoculated intraperitoneally (i.p.) with purified formalin-killed phase I and phase II Coxiella burnetii (C.b.) cells was dose-dependent. The phase I cells induced higher splenomegaly than phase II cells. The splenomegaly-inducing ability of phase I cells was reduced upon incubation with phase I but not with phase II antiserum, whereas the phase II cells preincubated with phase I or phase II immune sera induced higher splenomegaly than the phase II cells alone. Phase I cells caused lower splenomegaly in mice previously immunized with C.b. The splenomegaly-inducing ability of phase I cells was abolished by mild acid hydrolysis, by treatment either with phenol-chloroform-petroleum ether (PCP) or with a chloroform-methanol (CM) mixture. However, either the CM or the PCP-treated phase I cells retained their capacity to protect mice challenged with virulent phase I C.b.     

Proliferative glomerulonephritis in mice given intravenous Corynebacterium parvum

Mice given a killed suspension of Corynebacterium parvum (C.p.) developed nephritis as part of an immune complex disease. The nephritis was dose-related. After a single dose of 70 microgram (a human-equivalent dose) or of 466 microgram there was a mesangiopathic glomerulonephritis and after repeated human-equivalent doses there was a mesangiocapillary glomerulonephritis. Antibodies to C.p. increased and circulating immune complexes were detected. Mice receiving repeated doses also developed an arteritis. Study of this model may help in the understanding of human immune complex disease and the pathogenesis of glomerulonephritis.     

The effect of Corynebacterium parvum in influenza infected mice

This paper is the continuation of earlier studies on the effect of the killed suspension of Corynebacterium parvum in influenza virus infected mice. Our investigation showed the normalized effect of these drugs on disturbed function of cell mediated immunity during experimental influenza infection especially in phagocytic and bactericidal activity of granulocytes. The present experiments concern the explanation of these infection mechanisms. Intraperitoneal injection of Corynebacterium parvum stimulated spleen index. Foot pad test is higher than in comparatively treated BCG group. The pathomorphological analysis of the spleen, thymus and peritoneal lymph nodes points out to the multiplication of multiple lymph nodes sinus cells. Generally, C. parvum possessed protective effect in experimental influenza infection. We tested the following parameters: phagocytic and bactericidal activity of granulocytes, liberation of leukocytes migration inhibition factor (LIF).