Biomedical subjects

A M Attallah

Publications and source records attributed to A M Attallah.

At least 19 recordsLinked to original sources

PubMed2006

Susceptibility of neonate mice born to Schistosoma mansoni-infected and noninfected mothers to subsequent S. mansoni infection.

The present study tested the hypothesis that prenatal exposure of neonate Outbred albino mice to Schistosoma mansoni antigens (Ags) or antibodies (Abs) modulates their immunity against postnatal responses to infection. Persistence of maternal S. mansoni Abs and/or Ags in mice born to S. mansoni-infected mothers (IF-IMs) and noninfected mothers (IF-NMs) for up to 8 weeks after delivery was investigated. A higher level of anti-S. mansoni IgG Ab was detected in sera of 1-week-old mice born to IF-IM compared to controls. Then, immunoglobulin (Ig)G gradually decreased to the eight week. No anti-S. mansoni IgM Ab was detected in sera of these offspring at any week after delivery. Schistosoma Ags were detected in liver and kidney tissues of mice born to infected mothers. However, Ags decreased markedly till the sixth week in the liver but increased significantly at the sixth week in the kidney. Eight-week-old mice born to infected and noninfected mothers were infected with 200 S. mansoni ceracriae. Their sera and livers were collected for testing IgG and granuloma formation 6 weeks postinfection. Worms were collected via portal perfusion and counted. Anti-S. mansoni IgG level, size and number of liver granuloma, and worm burden were significantly reduced in the offspring of infected mothers. These data suggest that in utero exposure of Outbred albino mice to S. mansoni may attenuate the pathogenesis of S. mansoni in subsequent challenge.

Animals↗

PubMed2004

Vaccination of mice with a 30 kDa Schistosoma antigen with and without human adjuvant induces high protection against S. mansoni infection.

A 30 kDa antigen was characterized as a hydrophobic polypeptide containing 16 amino acids and evaluated as a potential candidate vaccine against infection by Schistosoma mansoni. CD1 albino mice immunized at 0, 14, and 21 days with 25 or 50 microg of the 30 kDa antigen per mouse with and without alum developed high levels of IgG antibodies (predominantly IgG2a and IgG2b isotypes). When immunized mice were infected with 200 S. mansoni cercariae, the highest protection levels (61% and 65% reduction in worm burden in two separate experiments) were obtained using the 50-microg antigen without alum adjuvant. The granuloma size decreased to 10%, a non-significant level in mice immunized using alum adjuvant. The results demonstrate the ability of the 30 kDa antigen with and without alum adjuvant to protect mice against S. mansoni infection.

Adjuvants, Immunologic↗

PubMed2003

Dysregulation of blood lymphocyte subsets and natural killer cells in schistosomal liver cirrhosis and hepatocellular carcinoma.

Immunological factors are important in the pathogenesis of a wide spectrum of hepatobiliary diseases. Using flow cytometry, we determined the changes in lymphocyte subsets and natural killer cells in 123 individuals (81 patients with liver disease and 42 healthy volunteers). The liver diseases included periportal fibrosis (PPF, 10 patients), liver cirrhosis (LC, 31 patients), and hepatocellular carcinoma (HCC, 40 patients). Schistosomiasis and viral hepatitis B and C were the putative etiological agents of liver diseases. Immunophenotyping by indirect immunofluorescence was conducted using monoclonal antibodies to CD3 (T-lymphocytes), CD4 (helper/inducer T-cells), CD8 (suppressor/cytotoxic T-cells), and CD57 (natural killer cells) cell surface markers. Immunophenotyping of PPF patients showed no significant changes in all markers compared with the healthy controls. However, there was a significant decrease ( P<0.01) in CD3 and CD4 T-cells, and a highly significant increase ( P<0.001) in CD57 T-cells in patients with LC or HCC. In addition, LC and HCC patients showed no significant change in CD8 T-cells compared with controls. In conclusion, the progression of liver diseases is associated with a dysregulation of cellular immune responses. T-lymphocytes and natural killer cells may play a role in the immunopathogenesis of liver cirrhosis and HCC.

CD4-CD8 Ratio↗

PubMed2002

Identification and characterization of a 26- to 28-kDa circulating antigen of Fasciola gigantica.

As a disease of domestic ruminants, fascioliasis is of considerable economic importance. Although serological tests are available for the diagnosis of the disease, they are of generally low specificity because of cross-reactivity with antigens from other parasites. There is a need to identify other Fasciola antigens on which more specific tests could be based. In the present study, a specific rabbit anti-serum and western-blot analyses were used to demonstrate the presence of a highly reactive antigen of 26-28 kDa not only in an extract of adult F. gigantica but also in the excretory/secretory products of the worms and in the bile secretions and sera of cattle that were naturally infected with this parasite. The 26- to 28-kDa antigen was isolated from preparative polyacrylamide gels, by electro-elution. The purified antigen showed a single peak at 5.8 min when analysed by capillary zone electrophoresis. It was characterized as protein containing 47.5% hydrophilic and 29.3% hydrophobic amino acids. Immunostaining demonstrated that the target epitope was located in the gut and tegument of adult F. gigantica and within the bile ducts, the portal tracts of the livers and the mucosa and muscularis of the gallbladders of infected cattle. A simple and rapid dot-ELISA technique based on the specific rabbit anti-serum was 100% specific when tested on the sera from nine cattle infected with F. gigantea and 27 uninfected cattle. In conclusion, the 26- to 28-kDa Fasciola antigen may be a promising candidate for the immunodiagnosis of fascioliasis.

Amino Acids↗

PubMed1999

DNA ploidy of liver biopsies from patients with liver cirrhosis and hepatocellular carcinoma: a flow cytometric analysis.

Flow cytometric DNA analysis was used to assess cellular kinetics of needle liver biopsies from patients with liver cirrhosis and hepatocellular carcinoma (HCC). An abnormal DNA content was shown in 44.5% of liver cirrhosis cases and in 78.6% of tumor sites. The number of proliferating cells (S + G2M%) was significantly increased in cirrhotic liver (P < 0.05). Dysplasia was found in 66% of cirrhotic specimens. All negative dysplasia specimens showed a diploid pattern while 69% of positive dysplastic specimens were aneuploid (P < 0.001). In conclusion, cell proliferation, aneuploidy and liver cell dysplasia are important indicators in liver cirrhosis for the development of HCC.

Adult↗

PubMed1999

Vaccination against Schistosoma mansoni infection using 74 kDa Schistosoma protein antigen.

An IgG2a anti-Schistosoma mansoni mouse monoclonal antibody was shown to passively protect Swiss mice. The 74 kDa target antigen was isolated from antigenic extracts of S. mansoni adult worms. Swiss and C57 BL/6J mice were immunized with 30, 50, 100 and 200 microg antigen/mouse doses with and without Freund's adjuvant. Sera of immunized mice showed high reactivity against 74 kDa antigen. The highest protection level (76.6% in Swiss mice and 50.1% in C57 BL/6J mice) was obtained using the 50 microg antigen dose with and without Freund's adjuvant. A marked reduction in granuloma number and intensity of collagen and reticular granuloma fibers was observed. The 74 kDa antigen has the ability to protect mice of different strains and to modulate the host immune system.

Adjuvants, Immunologic↗

PubMed1999

Induction of resistance against Schistosoma mansoni infection by passive transfer of an IgG2a monoclonal antibody.

Monoclonal antibodies can confer resistance to schistosome infections. This has led to identification of several protective antigens. An IgG2a monoclonal antibody designated BRL4 mAb identified a 74-kDa antigen in antigenic extract of Schistosoma mansoni adult worms. The target antigen was localized in gut and tegument. In 3 passive transfer experiments, the BRL4 mAb conferred 51.6, 41.9 and 53.8% protection levels into female Swiss mice. Histopathological examination revealed a marked decrease in number, size, collagen and reticular fibers of the liver granulomas. Further experiments using purified 74-kDa-target antigen as a candidate vaccine will be performed.

Animals↗

PubMed1999

Rapid detection of a Schistosoma mansoni circulating antigen excreted in urine of infected individuals by using a monoclonal antibody.

Schistosoma circulating antigens were used to indicate the infection intensity and to assess cure. An immunoglobulin G2a (IgG2a) mouse monoclonal antibody was used in a fast dot-enzyme-linked immunosorbent assay (ELISA; FDA) for rapid and simple diagnosis of schistosomiasis in the field. Seven hundred Egyptians were parasitologically examined for Schistosoma mansoni and other parasitic infections. A rectal biopsy was done as a "gold standard" for individuals showing no S. mansoni eggs in their feces. Egg counts were obtained by the Kato smear method for only 100 of 152 individuals with eggs in their feces. Specific anti-schistosome IgG antibodies were evaluated in sera by ELISA. Urine samples from the 700 individuals were tested by FDA for detection of the circulating antigen. The assay showed a sensitivity of 93% among 433 infected individuals and a specificity of 89% among 267 noninfected individuals. FDA showed the highest efficiency of antigen detection (91%) compared with the efficiency of antibody detection by ELISA (75%) and stool analysis (60%). In addition, FDA detected infected patients with 20 eggs/g of feces. Also, the sensitivity of FDA ranged from 90 to 94% among samples from patients with different clinical stages of schistosomiasis. All the assay steps can be completed within 30 min at room temperature for 96 urine samples. The monoclonal antibody identified a 74-kDa antigen in different antigenic extracts of S. mansoni and Schistosoma haematobium and in the urine of infected individuals. In addition, a 30-kDa degradation product was identified only in the urine samples. On the basis of these results, FDA should be used as a rapid tool for the sensitive and specific diagnosis of Schistosoma infection.

Adolescent↗

PubMed1999

Immunochemical characterization and diagnostic potential of a 63-kilodalton Schistosoma antigen.

Schistosoma circulating antigens were used for the detection of active infection. Anti-S. mansoni IgG2a monoclonal antibody (MAb) designated C5C4 was generated. The target epitope of this MAb was detected in adult worms, eggs, and cercariae antigenic extracts of S. mansoni and S. haematobium, had a molecular size of 63 kD, and was not detected in Fasciola hepatica and Ascaris. In addition, a 50-kD degradation product was identified only in the urine of infected individuals. Analysis by high-performance liquid chromatography of the purified antigen demonstrated only one peak. The 63-kD antigen was characterized as a protein containing 40.4% hydrophobic, 7.5% acidic, and 8.8% basic amino acids. The C5C4 MAb was used in a Fast Dot-ELISA for rapid and simple diagnosis of human schistosomiasis. The 63-kD circulating antigen was detected in 92% of urine samples from 330 S. mansoni-infected individuals, with 16% false-positive results among 130 noninfected individuals.

Adolescent↗

PubMed1998

Immunochemical purification and characterization of a 74.0-kDa Schistosoma mansoni antigen.

A polypeptide antigen of 74.0 kDa molecular weight was detected in the antigenic extracts of the 3 developmental stages of Schistosoma mansoni (eggs, cercariae, and adult worms) by western blotting using BRL4 monoclonal antibody (mAb) that significantly protected mice at the levels of 51.6%, 42%, and 53.8% against challenge S. mansoni infection in 3 separate experiments. This antigen was isolated and purified from crude soluble worm antigen preparation by immunoaffinity chromatography using CNBr-activated sepharose-4B beads coupled with the BRL4 mAb. The purified antigen showed a single peak when analyzed by both high-performance liquid chromatography and high-performance capillary electrophoresis. The 74-kDa antigen was characterized as a protein in nature with 56.9% hydrophilic amino acids and 43.1% hydrophobic amino acids. This antigen was detected in 93% of urine samples from infected cases with specificity of 89% among noninfected cases using an enzyme immunoassay-fast dot-enzyme-linked immunosorbent assay based on BRL4 mAb.

Adolescent↗

PubMed1997

Fast-Dot ELISA using urine, a rapid and dependable field assay for diagnosis of schistosomiasis.

The fast dot-enzyme linked immunosorbent assay (FD-ELISA) was used as a field applicable tool for rapid diagnosis of schistosomiasis. Seven hundreds faecal specimens were parasitologically examined for detection of S. mansoni eggs and other parasitic infection. Egg count was done for 100 infected patients. Rectal biopsies (394) were taken from individuals with no S. mansoni egg in their stool where it was used as a golden standard for diagnosis of schistosomiasis. Cross-reactivity with other parasites was studied. Serum samples were tested by ELISA technique for detection of human IgG anti-schistosomal antibodies. Seven hundreds urine samples (433 S. mansoni infected patients and 267 healthy individuals) were tested by FD-ELISA for detection of a schistosomal antigen excreted in urine using BRLF4 mouse monoclonal antibody. FD-ELISA results were compared with ELISA detecting antischistosomal IgG and stool analysis where, it showed highest efficiency (91%), compared with 81% and 60% for ELISA and stool analysis respectively. The sensitivity of FD-ELISA was high ranging from 90-94% in the four different clinical stages of schistosomiasis (Simple intestinal. Hepatosplenomegaly, Shrunken liver & Splenomegaly, and Shrunken liver-splenomegaly & ascites). FD-ELISA was highly sensitive, detecting infection cases with 20 eggs/gm faeces and its specificity was 89%. The antigen was characterized as a protein with a molecular weight of 74 KDa using western blot technique.

Adolescent↗

PubMed1996

Comparative study between cytology and dot-ELISA for early detection of bladder cancer.

Schistosomiasis remains one of the major public health problems of the tropics. Conservative estimates place the number of infected individuals at about 200 millions. In Egypt, carcinoma of the urinary bladder associated with schistosomiasis is the foremost oncologic problem, because of its high frequency and the late presentation of cases. A newly developed monoclonal antibody CK1K10 to keratinized grade 1 squamous cell carcinoma was used in a dot enzyme-linked immunosorbent assay (Dot ELISA) to test urine samples of 118 patients with bladder carcinoma, 291 patients with genitourinary pathology other than bladder carcinoma, in addition to 550 healthy controls. The overall sensitivity of the dot ELISA was 90% among 118 patients with bladder carcinoma. Twenty-seven of 33 transitional cell carcinoma cases (82%), 68 of the 71 squamous cell carcinoma cases (96%), 7 of 10 undifferentiated tumors cases (70%), and 4 of 4 adenocarcinoma were positive with this assay. The specificity was 90% in our sample population. A comparative study of diagnosis by cytology and dot ELISA was carried out in 57 patients with bladder carcinoma. Dot ELISA was found to be superior as a screening tool for high risk groups (P < .001 using chi-square test). Cytology detected 21% of transitional cell carcinoma, 68% of squamous cell carcinoma, 50% of adenocarcinoma, and 86% of undifferentiated tumors. The dot ELISA assay should be useful for screening high-risk groups because it does not require sophisticated equipment, is noninvasive, does not require highly trained staff, and can be performed in less than 30 minutes.

Adenocarcinoma↗

PubMed1991

UNME/K1: an IgG2a monoclonal antibody specific to cytokeratin of human urinary bladder squamous cell carcinoma.

The main distinctive feature of carcinoma in schistosomal bladder is keratinized squamous cell carcinoma. Keratins/cytokeratins constitute a multigeneic family of structurally related polypeptide markers for the malignant state of epithelial cells. A monoclonal antibody (UNME/K1) regognizing keratins associated with squamous cell carcinoma of the human urinary bladder was generated at the Urology and Nephrology Center, Mansoura, Egypt (UNME), by fusion of spleenocytes from a BALB/c mouse immunized with a keratin extract (K1) of human squamous cell carcinoma and P3X63Ag8/U1 syngeneic myeloma cells. UNME/K1 was purified by a protein-A affinity column and was of the IgG2a type, as determined by immunoelectrophoresis and gel diffusion techniques. When tested against keratins of different types of urinary bladder tumors using enzym linked immunosorbent assay (ELISA), UNME/K1 reacted only with the high molecular weight keratin of squamous cell carcinoma and showed selectivity towards specific histopathological grades of tumors.

Animals↗

PubMed1991

A dipstick, dot-ELISA assay for the rapid and early detection of bladder cancer.

A mouse monoclonal antibody (CK1K10) specific for keratin was developed. Enzyme immunoassays (EIAs) were performed to detect keratin in urine samples using CK1K10 and anti-mouse IgG. A high degree of sensitivity and specificity was obtained in the detection of bladder cancer patients. A fast dot-ELISA was developed in which urine is applied onto nitrocellulose (NC) sheets or dipsticks. Dipsticks coated with urine samples can be stored at room temperature for more than 5 days and at -20 degrees C for more than 3 months without loss of efficiency. A high positive correlation was found between the fast dot-ELISA and other EIAs. The assay does not require sophisticated equipment nor highly trained technical staff and can be performed in less than 30 min. The keratin dot-ELISA could be a reliable screening test for the early detection of bladder cancer.

Animals↗

PubMed1988

Cytokeratin shedding in urine: a biological marker for bladder cancer?

Cytokeratin shedding into the urine was measured using an enzyme-linked immunosorbent assay in 154 individuals. Samples include urines of normal controls, patients with urological conditions other than bladder cancer and bladder cancer patients. The assay results reflect the potential value of cytokeratin shedding in urine as a new urinary marker for bladder cancer. A 94% sensitivity for patients with squamous cell carcinoma of the bladder suggested the importance of using antibodies prepared against cytokeratin extracted from the same cell type of carcinoma as that to be detected. The relatively low sensitivity shown while detecting transitional cell carcinoma patients and the relatively low degree of assay specificity suggested the use of a panel of monoclonal antibodies specific to various types of cytokeratins of bladder carcinoma.

Adult↗

PubMed1988

Antibiotics and immunity: effects of antibiotics on mitogen responsiveness of lymphocytes and interleukin-2 production.

The immunomodulating properties of antimicrobial drugs may have important implications in prescriptive practice. This is particularly so for patients whose immune system has been compromised. In this study, tetracycline, cephalothin, rifampicin, polymyxin B and nitrofurantoin reduced mitogen responsiveness of both B and T lymphocytes of mouse spleen cells and human peripheral blood lymphocytes in vitro in a dose-dependent fashion. Ampicillin, chloramphenicol, gentamicin, streptomycin and erythromycin had no effect. In the in vivo study none of the antibiotics affected mouse spleen cell transformation in response to mitogen. The addition of interleukin-2 (IL-2) did not prevent the effect of the antibiotics tested on human lymphocytes in vitro. Cephalothin, chloramphenicol and gentamicin decreased IL-2 production by mouse spleen cells in vitro.

Animals↗

PubMed1987

Immunological activities of recombinant interferon-alpha 2 and its A fragment.

The immunomodulating effects of the A fragment of recombinant human interferon-alpha 2 (rIFN-alpha 2) generated by thermolysin treatment was compared to that of the intact rIFN-alpha 2 and lymphoblastoid IFN. The A fragment was similar to intact IFN in augmenting natural killer (NK) activity and suppressing the proliferation of certain cell lines, but it failed to inhibit human polyclonal immunoglobulin production; rIFN-alpha 2 and lymphoblastoid IFN were equally effective in suppressing this in vitro system. These data suggest that the A fragment mediates certain, but not all, of the immunomodulating properties of IFN-alpha 2.

Antibody Formation↗

PubMed1987

Immunopathology of experimental Schistosoma mansoni: immunohistochemical localization of parasite antigens in the host tissue.

Schistosoma mansoni antigens play a crucial role in the induction of immunopathological processes and in modulating the host immune system. A polyclonal rabbit antiserum to an antigenic fraction of adult schistosoma worms was used to localize worm and egg antigens in tissue sections of infected mice. Most granuloma formations identified in paraffin sections of portal tracts and intestinal mucosa were vigorous with florid cellular composition, consisting of macrophages and epithelioid cells, surrounding a central nidus of S. mansoni egg. Schistosome pigments were demonstrated at the periphery of the granuloma, within sinusoidal Kupffer's cells and within macrophages of intestinal mucosa. Large amounts of schistosome antigen were found sequestered in the mesenteric lymph nodes and in the spleen. A strong reaction for locally synthesized IgG was found. These findings suggest that the schistosome antigen-antibody complex found in the host lymphoreticular system plays a major role in the immunopathological process.

Animals↗