Klaus Janitschke

Animal Model Balamuthia Mandrillaris CNS Infection: Contrast and Comparison in Immunodeficient and Immunocompetent Mice: A Murine Model of “Granulomatous” Amebic Encephalitis

Balainnlhia mandrillaris and several species of Acanthamoeba are pathogenic “opportunistic” free-living amebas which cause granulomatous encephalitis (GAE) in humans and animals. The granulomatous component is negligible or absent, particularly in immunocompromised individuals. GAE is an “opportunistic” infection, usually seen in debilitated, malnourished individuals, in patients undergoing immunosuppressive therapy for organ transplants, and in Acquired Immunodeficiency Syndrome (AIDS). From around the world 156 cases of GAE have been reported from 1956 through October 1, 1995, 59 (26 in the USA) of them caused by B. mandrillaris, at least seven of them in AIDS patients. The present study was designed to compare and contrast the susceptibility of infection, the rate of infectivity and the histopathological changes within the CNS between the mutant, severe combined immunodeficient mice (SCID) infected with B. mandrillaris and the normal immunocompetent BALB-C mice. The SCID mouse is severely deficient in B and T lymphocytes, therefore lacking immunoglobulin and cell-mediated immunity. This mouse is also prone to develop early T cell lymphomas. One thousand amebic trophozoites and cysts of B. mandrillaris were intranasally and intraperitoneally inoculated in both strains of mice. Seventy percent of the intranasally inoculated SCID mice died due to CNS infection. Amebic trophozoites and cysts were found within CNS parenchyma without inflammatory response. Death occurred from 2 to 4 weeks after inoculation. By contrast only 10 percent of the intranasally inoculated BALB-C mice died with CNS infection showing the characteristic features of GAE. None of the intraperitoneally inoculated mice developed amebic infection. The SCID and BALB-C mice are logical models to study the structural alterations within the CNS of B. mandrillaris infection. This animal model recapitulates with excellent degree of fidelity several aspects of the pathogenesis and histopathological of free-living amebic infection in human beings.

Light and electron microscopy study of carbohydrate antigens found in the electron-lucent layer of Pneumocystis carinii cysts

Abstract The localization and biochemical nature of antigens found in the electron-lucent layer (ELL) of Pneumocystis carinii cysts using polyclonal rabbit antibodies are described. These antigens, specific for the cystic stages of the parasite, were shared by organisms from different hosts, suggesting that they represent functionally important components of the cyst cell wall. The binding sites were situated on an interwoven net of fibrils in the ELL produced by mild to strong proteolysis. Degradation of this residue by glucanase and chitinase confirms that this layer contains branched glucan and chitin. In contrast, the prompt susceptibility of the polysaccharide-rich ELL to proteolysis reveals that proteins are also relevant in building up the cyst-wall glucan skeleton. It is therefore concluded that the formation of the Pneumocystis cyst wall shows differences to the typical fungal cell-wall architecture. The taxonomical debate regarding this unique protist is ongoing, and consideration of these immunological and morphological findings may be useful for the study of the biology and phylogeny of Pneumocystis.

Untersuchungen ber die Wirtsspezifitt des geschlechtlichen Entwicklungszyklus von Toxoplasma gondii

Zwei der zur Familie der Felidae gehorenden echten Katzen Felis bengalensis (Prionailurus) und Schleichkatzen-artige der Familie Viverridae, 2 Viverra zibetha, 2 Paguma larvata und 3 Herpestes auripunctatus wurden oral mit Zysten und/oder Oozysten von Toxoplasma gondii infiziert. Nur bei Felis bengalensis konnte eine Ausscheidung von Toxoplasma-Oozysten im Kot nachgewiesen werden.

Light and electron microscopical study on sarcocysts from muscles of the rhesus monkey (Macaca mulatta), baboon (Papio cynocephalus) and tamarin (Saguinus (=Oedipomidas) oedipus)

SummarySarcocystis cysts from muscles of monkeys (baboon, tamarin and rhesus monkey) were studied by means of light and electron microscopy. The differences in the morphology of the cyst wall and parasites clearly indicate that the three monkey species examined were each parasitized by at least a specific Sarcocystis species being not identical with S. nesbitti or S. kortei. The large numbers of cysts found within the muscle fibres point out the important role that have these monkeys as intermediate hosts in the life cycle of Sarcocystis species, where the final hosts are still unknown.

Nitrocellulose dot-ELISA for serodiagnosis of schistosomiasis

The diagnostic value of the nitrocellulose (NC)-ELISA technique originally described for the detection of viral and bacterial antigens was studied for the detection of antibodies in patients with parasitologically confirmed schistosomiasis, using only about 100 ng total protein content per NC disc of Schistosoma mansoni soluble egg antigen supplied by WHO. The results showed excellent sensitivity: 100% (38/38) for S. mansoni cases and 93.6% (44/47) for S. haematobium. The specificity tested on 50 sera of persons from non-endemic areas was also 100%. 34 sera of patients suffering from other parasitoses were also included. 3 sera of 10 from filariasis cases reacted positively by NC-ELISA, but they were also positive by indirect immunofluorescence, indicating a possible undetected Schistosoma infection. One positive reaction among sera from 4 toxocariasis cases was not confirmed by further tests. We conclude that the NC-ELISA can be a useful technique, especially in developing countries where tests with low cost equipment are needed. Large-scale screening studies should be done to evaluate its usefulness under field conditions.

Beitrag zum Entwicklungszyklus von Sarkosporidien der Grantgazelle (Gazella granti)

SummaryWe have been able to observe macro- and microscopically sarcosporidial cysts in the muscles of a Grants Gazelle. Dogs and cats fed with these cysts shed occysts and sporocysts in their feces, indicating that they both are the final hosts of the Sarcosporidia in Grants Gazelle.ZusammenfassungIn der Muskulatur einer Grantgazelle (Gazella granti) konnten makro-und mikroskopisch sichtbare Sarkosporidienzysten nachgewiesen werden. Hund und Katze schieden nach Verfütterung dieser Stadien Oozysten bzw. Sporozysten mit dem Kot aus. Beide Tierarten sind daher Endwirte von Sarkosporidien der Grantgazelle.

Pränatale Übertragung der Toxoplasmen von der Mutter auf das Kind

ZusammenfassungIn dem vorliegenden Beitrag wird zunächst über die Infektion der Schwangeren mit Toxoplasmen sowie über die Laboratoriumsdiagnostik bei der Mutter, dem Fötus und Neugeborenen berichtet.Danach werden die Folgen für das Kind und die Chemotherapie dargestellt. Zudem wird eingehend die Vorbeugung und die Vorsorgeproblematik behandelt sowie auf die Meldepflicht eingegangen.SummaryA report is given on the infection of pregnant women with Toxoplasma and on the laboratory diagnosis on mother, fetus and newborn. The next chapters deal with the consequences for the child and its chemotherapy. Prevention and problems of mother care are discussed in detail, as well as the infection as a notifiable one.

Immunity to Acanthamoeba culbertsoni: experimental studies with Acanthamoeba and control antigen preparations

Mice were intranasally immunized with living and killed Acanthamoeba as well as culture supernatant, living Toxoplasma and BCG, and challenged with pathogenic A. culbertsoni strain A-1. The best protection was achieved with killed amoebae of the same strain. A high rate of mortality was observed in immunized mice treated with immunosuppressives and challenged with A. culbertsoni A-1. The significance of the results in relation to environmental human infection is discussed.

Untersuchungen über die Möglichkeit der Übertragung von Toxoplasmen durch Bluttransfusionen

ZusammenfassungDas Vorkommen von Toxoplasmen im Blut von Blutspendern ist beschrieben worden. In eigenen Versuchen konnte nachgewiesen werden, daß die Parasiten in Blutkonserven mehrere Wochen überleben können. Aus Blutproben von 1500 untersuchten Spendern konnten in keinem Falle Toxoplasmen im Tierversuch angezüchter werden. Bei 75 bis 80% der Personen waren Toxoplasma-Antikörper nachweisbar, die bei 4,2%Sabin-Feldman-Test (SFT)/Komplementbindungsreaktion (KBR)-Werte von ≧1∶1000/≧1∶10 aufwiesen. Der Bluttransfusion scheint im Hinblick auf die Übertragung der Toxoplasma-Infektion keine epidemiologische Bedeutung zuzukommen.Im Einzelfalle (s. Diskussion) sollte von einer Spende und Transfusion abgesehen werden.SummaryThe occurrence of toxoplasms in the blood of donors has already been described. In own experiments we have been able to demonstrate that the parasites might survive in stored blood for several weeks. In blood specimens from 1500 donors examined, toxoplasms could not be cultured in the mouse inoculation test in any of these cases. In 75% to 80% of the persons examined, Toxoplasma antibody titres could be demonstrated, 4.2% of which had dye test/CFT values of ≧1∶1000/≧1∶10.Blood transfusion does not seem to have epidemiological significance in regard to the transmission of Toxoplasma infection. In single cases (see discussion), donation and transfusion should not be performed.

Detection of antibody formation in mice, rats and rabbits immunized with different Pneumocystis carinii antigens.

Antibody formation to P. carinii of human origin was determined by an indirect immunofluorescence antibody assay (IFA) after immunization of mice, rats and rabbits with pronase-treated whole cysts and soluble antigen in order to obtain more detailed data about the production of polyclonal antibodies. Antibody titre profiles over defined periods have shown that noticeable differences between the immunoreactions to whole cysts and soluble antigen occur. The soluble antigen produced an earlier and stronger titre rise (peak titres of up to 1:2560 2 to 4 weeks after immunization). In contrast to this, whole cysts produced equally high, although retarded, antibody titre peaks only in normal mice and rats and when the dose had been doubled. Nu/nu mice failed to demonstrate any reaction to these P. carinii immunogens. Cross-reactivity of the antibodies with P. carinii antigen from rat lungs was demonstrated. Possible reasons for different immunoreactions to these antigens, the importance of proteolytic digestion for the results obtained and the potential applicability of these polyclonal antibodies to a histochemical demonstration of the parasite are discussed.