Analysis of Cellular Response and Gamma Interferon Synthesis in Bronchoalveolar Lavage Fluid and Lung Homogenate of Mice Infected with Pneumocystis carinii

The cellular and cytokine responses in the lungs of mice infected with Pneumocystis carinii were examined on both lung homogenates and bronchoalveolar lavage (BAL) fluids. In the lungs of infected mice, the number of P. carinii cysts rapidly decreased by day 7, then started to increase with a peak on day 14, and thereafter decreased gradually. When the presence of P. carinii was examined at the DNA level by dot blot hybridization, a similar clearance curve was obtained, and the organisms were shown to be completely eliminated on day 28. In the late phase of infection, leukocytes, mainly lymphocytes, increased in number when analyzed on lung homogenates, while no significant increase of inflammatory cells was observed in BAL fluids. An accumulation of both CD4⁺ and CD8⁺ T cells and an increase of activated T cells expressing IL-2Rα were observed in lung homogenates of the infected mice. In addition, a considerable amount of IFN-γ was detected in lung homogenates, but not in BAL fluids. These data indicate that lung homogenates are more suitable than BAL fluids for the analysis of cellular and cytokine responses in the lungs of mice infected with P. carinii. To define the involvement of IFN-γ in host defense against P. carinii, the effect of this cytokine on the killing activity of macrophages against P. carinii was examined in vitro. IFN-γ was found to augment this activity by increasing nitric oxide synthesis of the macrophages. Thus, it is suggested that IFN-γ plays an important role in the protection of mice from P. carinii infection.     

Interstitial pneumonia in immunocompetent laboratory rats caused by natural infection with Pneumocystis carinii

Pneumocystis (P.) carinii is known to cause fatal pneumonia in immunocompromised rats. Cases of P. carinii interstitial pneumonia in immunocompetent rats have been shown histologically to present with perivascular lymphoid cuffs, which have previously been attributed to rat respiratory virus. This study aims to determine the prevalence and pathological characteristics of P. carinii in immunocompetent laboratory rats in experimental facilities in Japan. An epidemiological survey for this agent was performed using PCR to assess 1,981 immunocompetent rats from 594 facilities in Japan. We observed that 6 of the 1,981 rats (0.30%) from 4 out of 594 facilities (0.67%) were positive for P. carinii without infection of other known pathogens. Gross pulmonary lesions were found in 4 of the 6 affected rats. The lungs of these rats contained scattered dark red/gray foci. Histopathologically, the lungs exhibited interstitial pneumonia with lymphoid perivascular cuffs: Pneumocystis cysts were observed using Grocott’s methenamine silver stain. To our knowledge, this report is the first to reveal the prevalence of natural P. carinii infection in immunocompetent laboratory rats in Japan.     

Inoculated mouse model of Pneumocystis carinii pneumonia.

A transtracheally inoculated mouse model of Pneumocystis carinii has been developed using BALB/c mice, a widely available strain free of latent P. carinii infection. The mean infectivity score of untreated inoculated mice was 4.1 compared to the mean infectivity score of 0.1 for trimethoprim/sulfamethoxazole (50/250 mg/kg) treated inoculated mice, approximately a four-log difference. An inoculated mouse model of P. carinii infection provides both a source of organisms from a different host and an animal model for study of drugs for therapy and prophylaxis which is less costly than rats and which requires less drug than required for rats.     

Study on the therapeutic effects of interferon and gamma-globulin in experimental Pneumocystis carinii pneumonia]

This study was performed to observe the therapeutic effects of interferon-gamma(IFN-gamma) and gamma-globulin(gamma-globulin) in experimental Pneumocystis carinii pneumonia of immune suppressed mice. After 9 weeks, trimethoprim-sulfamethoxazole(TMP-SMZ; 10-50 mg/mouse/day), mouse IFN-gamma(5 x 10(4) units/mouse/day) and mouse gamma-globulin(20 mg/mouse/day) were administered to the mice for 3 weeks by the experimental group. The therapeutic efficacy was evaluated by body weights, histopathologic and electron microscopic findings of the lungs, and number of P. carinii cysts by Gomori's methenamine silver stain. Body weights of the mice were significantly increased in the group of combination therapy of TMP-SMZ with IFN-gamma or gamma-globulin, and in the group of TMP-SMZ treatment (p < 0.05), however, little effect was found in the group of gamma-globulin alone. Histopathologic findings of P. carinii pneumonia were much improved in the group of combination therapy of TMP-SMZ with IFN-gamma. Treatment with either TMP-SMZ or IFN-gamma significantly reduced the number of cysts in the P. carinii pneumonia, but gamma-globulin alone was ineffective. In electron microscopic findings of P. carinii pneumonia, the number of trophozoites and cysts were reduced by treatment with either TMP-SMZ or IFN-gamma, and most of the cysts were empty or containing one or two intracystic bodies. The present results suggested, that combination therapy of TMP-SMZ with IFN-gamma had synergistic effects in treatment of P. carinii pneumonia in experimental mice.     

Value of anti-infective chemoprophylaxis in primary systemic vasculitis: what is the evidence?

Although infections are a major concern in patients with primary systemic vasculitis, actual knowledge about risk factors and evidence concerning the use of anti-infective prophylaxis from clinical trials are scarce. The use of high dose glucocorticoids and cyclophosphamide pose a definite risk for infections. Bacterial infections are among the most frequent causes of death, with Staphylococcus aureus being the most common isolate. Concerning viral infections, cytomegalovirus and varicella-zoster virus reactivation represent the most frequent complications. The only prophylactic measure that is widely accepted is trimethoprim/sulfamethoxazole to avoid Pneumocystis jiroveci pneumonia in small vessel vasculitis patients with generalised disease receiving therapy for induction of remission.     

Pneumocystis Carinii Pneumonia: Relationship Between Cyst Size and Response to Treatment

Pneumocystis carinii pneumonia is a common cause of death in patients with AIDS. Diagnosis is based on cytological examination of smears prepared from induced sputum samples and bronchoalveolar lavage (BAL) specimens which have been stained with methenamine silver. We have examined 46 BAL/induced sputum specimens from patients who had clinical symptoms and signs suggestive of P. carinii pneumonia and measured the diameter of a minimum 100 cysts in each specimen. We found that cyst size correlated with response to treatment with co-trimoxazole. This observation has implications for the therapeutic management of patients with this infection. La pneumopathie áPneumocystis carinii est une cause de décès fréquente chez les patients atteints d'un syndrome d'immunodéficience acquise (SIDA). Le diagnostic est basé sur l'examen cytologique des frottis préparés à partir du produit d'expectoration provoquée ou du liquide de lavage bronchoalvéolaire (LBA), après coloration de Grocott. Le diamètre d'au moins 100 kystes par échantillon a été mesuré dans 46 prélèvements de LBA/expectoration provoquée de patients présentant des signes cliniques suggérant une pneumopathie àPneumocystis carinii. Nous avons constaté que le diamètre des kystes est corrélé avec la réponse au traitment par co-trimoxazole, Cette observation a des implications sur la conduite du traitement des patients porteurs de cette infection. PCP ist eine häufige Todesursache bei HIV-Patienten. Die diagnose beruht auf dem cytologischen Nachweis in induzierten Sputumausstrichen oder bronchio-lo-alveolären Lavagen mit der Grokott-Färbung. In 46 positiven Fällen wurde der Durchmesser von mindestens 100 Cysten in jeder Probe gemessen und eine Korrelation zum Behandlungserfolg mit Co-Trimoxazol nachgewiesen.     

Polymorphism of the Thymidylate Synthase Gene of Pneumocystis carinii from Different Host Species

Pneumocystis carinii is an opportunistic agent found in the lung of various mammals which often causes severe pneumonia in immunocompromised humans, especially in AIDS patients. In the past several years significant additions have been made to the collection of knowledge we have concerning the genetic diversity of P. carinii. These additions provide new understanding of Pneumocystis transmission and the effect of possible reservoirs of Pneumocystis in the various species. In this study, a 400-bp fragment of the thymidylate synthase (TS) gene of P. carinii has been amplified by PCR from 43 parasite isolates obtained from 4 mammalian host species: rat, mouse, rabbit and human. A probe selected from the TS gene sequence of rat-derived P. carinii was hybridized with the amplified products from rat- and mouse-derived P. carinii, but not with rabbit or human P. carinii DNA. Restriction profiles were performed on amplified fragments from all isolates, and the 4 nucleotide sequences of the TS gene fragment amplifed from rat, mouse, rabbit and human P. carinii were determined. Differences were detected in the gene fragment in P. carinii isolates from the 4 host species; however no difference was revealed in P. carinii isolates within a single host species, whatever the host strain or its geographic origin. Thus, the sequence differences of the P. carinii TS gene appeared as host-species specific. A specific probe which recognized all human P. carinii isolates was defined.     

Population Structure of Rat-Derived Pneumocystis carinii in Danish Wild Rats

The rat model of Pneumocystis carinii pneumonia is frequently used to study human P. carinii infection, but there are many differences between the rat and human infections. We studied naturally acquired P. carinii in wild rats to examine the relevance of the rat model for human infection. P. carinii DNA was detected in 47 of 51 wild rats and in 10 of 12 nonimmunosuppressed laboratory rats. Evidence for three novel formae speciales of rat-derived P. carinii was found, and these were provisionally named Pneumocystis carinii f. sp. rattus-secundi, Pneumocystis carinii f. sp. rattus-tertii, and Pneumocystis carinii f. sp. rattus-quarti. Our data suggest that low-level carriage of P. carinii in wild rats and nonimmunosuppressed laboratory rats is common and that wild rats are frequently coinfected with more than one forma specialis of P. carinii. We also examined the diversity in the internally transcribed spacer (ITS) regions of the nuclear rRNA operon of Pneumocystis carinii f. sp. carinii by using samples from wild rats and laboratory rats and spore trap samples. We report a lack of variation in the ITS1 and ITS2 regions that is consistent with an evolutionary bottleneck in the P. carinii f. sp. carinii population. This study shows that human- and rat-derived P. carinii organisms are very different, not only in genetic composition but also in population structure and natural history.     

Pneumocystis Pneumonia: Epidemiology and Options for Prophylaxis in Non-HIV Immunocompromised Pediatric Patients

The pediatric population of non-HIV immunocompromised patients at risk for Pneumocystis pneumonia (PCP) continues to increase. While prophylactic therapy can be highly effective in preventing this opportunistic pathogen, identifying the at-risk populations appropriate for use of prophylaxis and navigating the risks and benefits of each therapeutic option can be challenging. In this article, the available epidemiology for baseline rates of PCP is presented for a variety of non-HIV immunocompromised pediatric populations. Additionally, the comparative effectiveness and side effect profiles for trimethoprim/sulfamethoxazole, dapsone, atovaquone, and pentamidine are discussed. Institutions are encouraged to review the data and to establish and implement a local practice guideline for PCP prophylaxis that can be monitored for effectiveness over time. An example of a standardized practice guideline is suggested.     

Therapeutic Potential of Caspofungin Combined with Trimethoprim-Sulfamethoxazole for Pneumocystis Pneumonia: A Pilot Study in Mice

Pneumocystis pneumonia (PcP) is a major cause of mortality and morbidity in immunocompromised patients. There are limited alternative therapeutic choices to trimethoprim-sulfamethoxazole (TMP-SMX) which is the standard first line therapy/prophylaxis for PcP. The efficacy of low doses of caspofungin and caspofungin in association with TMP-SMX standard-prophylactic dose was evaluated in an experimental model of Pneumocystis. Susceptibility of Pneumocystis spp. to low doses of caspofungin and caspofungin/TMP-SMX was evaluated in Balb/c immunosuppressed mice, infected intranasally with P. murina. Caspofungin was administered once daily at 0.1 mg/kg, 0.05 mg/kg, and 0.001 mg/kg and TMP-SMX was administered by oral gavage (12.25 mg/62.5 mg/day), for 21 days. Efficacy was calculated based on the reduction in organism burden determined through quantitative fluorescent-based real-time PCR (qPCR). Serum β-1,3-D-glucan was measured as an additional marker of infection. The present data showed that caspofungin demonstrated anti-Pneumomocystis effect. However, the doses administrated were too low to achieve Pneumocystis eradication, which suggests that echinocandin treatment should not be administrated as mono-therapy. After 21 days of treatment, P. murina was not detected in the lungs of mice with either TMP-SMX or caspofungin/TMP-SMX. The results showed that, even at the lowest concentrations tested, the efficacy of caspofungin in association with TMP-SMX was higher than the efficacy of either drug used alone. The administration of caspofungin/TMP-SMX was at least 1.4 times more effective against P. murina infection than TMP-SMX used alone. The most promising result was achieved with the combination of caspofungin 0.05 mg/kg/day with TMP-SMX 12.5 mg–62.5 mg/day, which reduced the parasite burden to undetectable levels immediately at the 14^th day of treatment, showing a highly marked anti-Pneumomocystis effect. These data suggest that the administration of low doses of caspofungin in combination with low doses of TMP-SMX may provide an improved treatment protocol for Pneumocystis infection clearance.     

In vitro attachment of Pneumocystis carinii from mouse and rat origin

Summary— The attachment of Pneumocystis carinii to lung cells could play a role in the pathophysiology of P carinii pneumonia. The trophozoite attaches to type I alveolar epithelial cells. Physical, chemical, and extracellular matrix factors, involved in the mouseor rat-derived P carinii attachment to fibroblastic cells in culture, were examined using a new model of in vitro adherence. The development of parasite filopodia penetrating deeply the host cell cytoplasm was observed using transmission electronic microscopy. Killed P carinii organisms were unable to attach to cultured cells. Also, parasites were unable to attach to killed target cells. The P carinii in vitro attachment was partially inhibited by cytochalasin B. In contrast, the parasite attachment was not affected when the target cell cytoskeleton was altered. In our work conditions, sialic acids were not involved in the attachment process. Present results showed that fibronectin (Fn) plays a role in the parasite attachment, and suggest that a specific Fn-binding receptor is present at the surface of mouse-derived P carinii organisms.     

Green synthesis of zinc nanoparticles using Lavandula angustifolia Vera. Extract by microwave method and its prophylactic effects on Toxoplasma gondii infection

BackgroundToday, a suitable vaccine has not yet been discovered to prevent Toxoplasma gondii infection. Therefore, prophylaxis can be suggested as the preferred approach to prevent toxoplasmosis. This study aims to evaluate the prophylactic effects of synthesized zinc nanoparticles (ZnNPs) using Lavandula angustifolia Vera., by microwave method on chronic toxoplasmosis in mice.MethodsBALB/c Mice orally administrated with ZnNPs the doses of 32.5, 75, 150 mg/kg/day for two weeks. On the 15th day, the mice were intraperitoneally infected with the Tehran strain of T. gondii (25 tissue cysts). The mean diameter and the numbers of brain tissue cysts, as well as the mRNA levels of inducible nitric oxide synthesize (iNOs), and interferon-gamma (IFN-γ) in mice of each experimental group were evaluated.ResultsThe synthesized ZnNPs represent a spherical form with a size ranging from 30 to 80 nm. The results revealed that oral administration of Zn NPs at the doses of 32.5 (p < 0.001) and 75 mg/kg/day (p < 0.001) for 14 days significantly reduced the mean number and diameter of the brain tissue cysts in tested mice. No T. gondii tissue cyst was observed after oral administration of Zn NPs at the doses of 150 mg/kg. Based on the results of Real-time PCR analysis, the expression level of IFN-γ and iNOs was significantly increased (p < 0.001) in mice treated with 32.5, 75, 150 mg/kg/day for two weeks.ConclusionThe obtained findings of the current investigation exhibit the significant prophylactic effects of ZnNPs against chronic toxoplasmosis in mice; so that oral administration of ZnNPs the doses 32.5, 75, 150 mg/kg reduced the parasite load and even completely controlled the infection in mice. The results show that the ZnNPs had strengthened the innate immune system which could be the reason for its strong prophylactic effects. However, further in vivo and clinical investigations are required to confirm these results as well as other possible mechanisms that can trigger these pharmacological properties.     

Multi-Gene Family of Major Surface Glycoproteins of Pneumocystis carinii: Full-Size cDNA Cloning and Expression

The major surface glycoprotein (MSG) of Pneumocystis cariniiplays a crucial role in the fatal pneumonia caused by this organismin AIDS patients. A cDNA encoding a full-length MSG polypeptidewas isolated from a phage library of rat-derived P. cariniicDNAs. The deduced MSG, referred to as the MSG5 subtype, isa 120,765-Da protein composed of 1,076 amino acids and containsan anchoring hydrophobic sequence at the C-terminus of the protein.Sequence analyses of cloned MSG-cDNAs revealed an MSG-gene familywith 70% protein sequence identity between subtypes. P. cariniikaryotype hybridization analyses indicated that the MSG genefamily members are scattered throughout most of the P. cariniichromosomes. These recombinant MSG proteins reacted with theantiserum from P. carinii-infected rats, as expected, and antiserumgenerated against P. carinii-infected mice, indicating the existenceof common determinants in MSG polypeptides. The family of MSGproteins is rich in cysteine residues and these cysteine arehighly conserved in all MSG subtypes regardless of species specificity,suggesting the structural and/or functional importance of thesecysteine. The pathobiological significance of the MSG gene familyand its sequence diversity in P. carinii is discussed.     

Evidence of Airborne Excretion of Pneumocystis carinii during Infection in Immunocompetent Rats. Lung Involvement and Antibody Response

To better understand the role of immunocompetent hosts in the diffusion of Pneumocystis in the environment, airborne shedding of Pneumocystis carinii in the surrounding air of experimentally infected Sprague Dawley rats was quantified by means of a real-time PCR assay, in parallel with the kinetics of P. carinii loads in lungs and specific serum antibody titres. Pneumocystis-free Sprague Dawley rats were intratracheally inoculated at day 0 (d0) and then followed for 60 days. P. carinii DNA was detected in lungs until d29 in two separate experiments and thereafter remained undetectable. A transient air excretion of Pneumocystis DNA was observed between d14 and d22 in the first experiment and between d9 and d19 in the second experiment; it was related to the peak of infection in lungs. IgM and IgG anti-P. carinii antibody increase preceded clearance of P. carinii in the lungs and cessation of airborne excretion. In rats receiving a second challenge 3 months after the first inoculation, Pneumocystis was only detected at a low level in the lungs of 2 of 3 rats at d2 post challenge and was never detected in air samples. Anti-Pneumocystis antibody determinations showed a typical secondary IgG antibody response. This study provides the first direct evidence that immunocompetent hosts can excrete Pneumocystis following a primary acquired infection. Lung infection was apparently controlled by the immune response since fungal burdens decreased to become undetectable as specific antibodies reached high titres in serum. This immune response was apparently protective against reinfection 3 months later.     

The Diagnosis of Pneumocystis Carinii Pneumonia By Cytologic Evaluation of Papanicolaou and Leishman-Stained Bronchoalveolar Specimens In Patients With the Acquired Immunodeficiency Syndrome

The presence of foamy alveolar casts or flocculent material in Papanicolaou and Leishman-stained smears of bronchoalveolar lavage (BAL) fluid is said to be indicative of infection with Pneumocystis carinii. We have investigated the sensitivity and specificity of this method of diagnosing pneumocystis pneumonia in patients with the acquired immunodeficiency syndrome (AIDS). Patients (n= 114) with diffuse lung infiltrates were submitted to fibreoptic broncoscopy and BAL. Seventy of them were patients with AIDS. the other 44 individuals were not infected by the human immunodeficiency virus (HIV). Pneumocystis carinii organisms were identified on Grocott's methenamine silver (GMS)-stained BAL smears in 30 patients with AIDS. Flocculent material was present in the Papanicolaou and Leishman-stained smears from all of these cases. Conversely, P. carinii were not seen on GMS-stained smears in the remaining 84 individuals with or without AIDS. No flocculent material was observed in Papanicolaou or Leishman-stained smears in these 84 patients. We concluded that the presence of flocculent material in Papanicolaou or Leishman-stained smears of BAL fluid is indicative of P. carinii pneumonia in patients with AIDS. La présence de cylindres alvéolaires spumeux ou de matériel floculé dans les étalements de liquide de lavage bronchoalvéolaire (LBA) colorés selon Papanicolaou ou Leishman est considérée comme symptomatique d'une infection par Pneumocystis carinii. Nous avons étudié la sensibilité et la spécificité de cette méthode de diagnostic de l'infection par Pneumocystis carinii chez des patients atteints de syndrome de déficience immunitaire acquise (SIDA). Cent quatorze malades avec des infiltrats pulmonaires diffus ont subi une fibroscopie bronchique et un lavage broncho-alvéolaire. Soixante dix d'entre eux edtaient atteints de SIDA, 44 n'étaient pas infectés par le Virus de l'Immunodéficience Humaine (VIH). Le Pneumocystis carinii a été identifiié par la coloration de Grocott chez 30 patients atteints de SIDA. Chez ces patients, la présence d'un matériel floculé est constante sur les étalements colorés au Papanicolaou et au Leishman. A l'inverse, Pneumocystis carinii n'a pas été retrouvé chez les 84 autres malades, atteints ou non du SIDA et les étalements de LBA ne contenaient pas de matériel floculé. En conclusion, la présence de matériel floculé dans les étalements de LBA colorés selon Papanicolaou ou Leishmanest associée à une pneumpathie àPneumocystis carinii chez les patients atteints de SIDA. Sensitivität und Spezifität des Nachweises schaumiger oder flockiger Alveolarausgüsse bei Pneumocystis carinii wurden in 114 Fällen diffuser Lungeninfiltrate untersucht. 70 Patienten waren an AIDS erkrankt, 44 weitere waren HIV-negative. In 30 der AIDS-Fälle wurde P. carinii mit der Grocott'schen Färbung nachgewiesen. Die typischen Eiweißniederschläge waren in all diesen Fällen nachweisbar. Umgekehrt ergab die Grocottfärbung in 84 Fällen mit oder ohne AIDS ein negatives Ergebnis. In all diesen Fällen war kein Eiweißniederschlag nachweisbar. Daraus ergibt sich, daß die Eiweißniederschläge in Präparaten, die nach Papanicolaou oder Leishman gefärbt wurden, kennziechned sind für die P. carinii Pneumonie.     

Physiological characteristics ofClostridium bifermentans selectively isolated from California desert tortoise

A selective agar medium containing cycloserine (250 mg/L), sulfamethoxazole (76 mg/L), and trimethoprim (4 mg/L) was used for isolation ofClostridium bifermentans from the intestinal contents of California desert tortoise. Typical lecithinase positive colonies that appeared on the plates, were biochemically characterized with the API 20A System and a conventional procedure. The susceptibility of the isolates to 12 antimicrobial agents was determined by the broth microtitration technique using the ANA MIC System.C. bifermentans strains were shown to be highly susceptible to cefoxitin, cefotetan, ceftizoxime, cefotaxime, chloramphenicol, clindamycin, penicillin, metronidazole, piperacillin, ticarcillin, and mezlocillin. Less than 10% of the isolates exhibited resistance to tetracycline. All strains were found to be highly resistant to cycloserine, sulfamethoxazole, and trimethoprim. The GLC analysis of the culture supernatants for volatile fatty acids revealed the presence of formic, acetic, isobutyric, butyric, isovaleric, and isocaproic acids.     

Treatment efficacy of trimethoprim sulfamethoxazole, pentoxifylline and altrenogest in experimentally induced equine placentitis

The objective was to determine if long-term treatment with trimethoprim sulfamethoxazole (antimicrobial), pentoxifylline (anti-inflammatory/anti-cytokine) and altrenogest (synthetic progestin), would improve pregnancy outcome in mares with experimentally induced placentitis. Seventeen normal, pregnant pony mares were enrolled in the study at 280-295 d of pregnancy. Placentitis was induced in all mares by intra-cervical inoculation of Streptococcus equi subsp. zooepidemicus (10⁷ CFU). Five mares served as infected, untreated control animals (Group UNTREAT). Twelve mares (Group TREAT) were infected and given trimethoprim sulfamethoxazole (30 mg/kg, PO, q 12h), pentoxifylline (8.5 mg/kg, PO, q 12h) and altrenogest (0.088 mg/kg, PO, q 24h) from the onset of clinical signs to delivery of a live foal or abortion. Blood samples were cultured from all foals at delivery and fetal stomach and thoracic contents were obtained for culture from dead fetuses. More mares in Group TREAT delivered viable foals (10/12; 83%; P < 0.05) than mares in Group UNTREAT (0/5; 0%). Ten of 12 foals (83%) in Group TREAT had negative blood cultures at birth. All foals in Group UNTREAT (5/5; 100%) had positive cultures from one or more samples (blood, stomach contents, and thoracic fluid). Bacteria were recovered from uterine culture samples in both groups. Streptococcus equi subsp. zooepidemicus was the predominant organism recovered from fetal/foal or mare culture samples. The authors inferred that administration of trimethoprim sulfamethoxazole, pentoxifylline and altrenogest may improve the viability of foals from mares with experimentally induced placentitis.     

Identification of Phagocytosed Pneumocystis Carinii In Human Pulmonary Alveolar Macrophages

Examination of Papanicolaou-stained bronchoalveolar lavage samples from cases with Pneumocystis carinii pneumonitis under ultra-violet light reveals alveolar macrophages packed with fluorescent inclusions. Immunoenzymatic staining of the alveolar macrophages with a monoclonal antibody specific for P. carinii (3F6) showed that these inclusions contain intact pneumocysts or their degradation products. Fluorescence microscopy of Papanicolaou-stained smears is advocated as a sensitive and specific method of diagnosing P. carinii infection.     

The Molecular Characterization and Immunity Identification of Rhoptry Protein 22 of Toxoplasma gondii as a DNA Vaccine Candidate Against Toxoplasmosis

Toxoplasma gondii (T. gondii) rhoptry proteins (TgROPs) have been considered main targets and indicator molecules for immune diagnosis and prophylaxis since they initially present during the process of invasion. In this study, the effect of intramuscularly injecting the genetic vaccine pVAX‐ROP22 was evaluated, made by inserting the TgROP22 sequence into the eukaryotic expression vector of pVAX I, into BALB/c mice. The levels of IgG, IgG1, and IgG2a in pVAX‐ROP22 vaccinated animals were integrally increased. It was uncovered by cytokine profile analyses that the levels of IFN‐γ and IL‐2 were significantly increased, while no significant changes were detected in IL‐4 and IL‐10 levels. In addition, we found that immunization with pVAX‐ROP22 significantly prolonged the survival time (13.80 ± 1.75 d) of mice after challenge infection with the virulent T. gondii RH strain, in comparison with those of control animals (died within 10 d). Moreover, the number of brain cysts (1,406 ± 277) in the animals subjected to pVAX‐TgROP22 vaccination decreased remarkably (P < 0.05) compared with the blank control mice (2,333 ± 473), and the size of brain cysts in pVAX‐TgROP22 group was significantly smaller than the groups of blank, PBS and pVAXI. These results suggested that TgROP22 as DNA vaccine could trigger strong humoral and cellular responses and induce partial protection against toxoplasmosis.