Detection of Cryptosporidium parvum oocysts in calf fecal samples by direct immunofluorescence assay / Detecção de oocistos de Cryptosporidium parvum em amostras fecais de bezerros pela reação de imunofluorescência direta

The aim of this study was to produce a conjugate containing anti-Cryptosporidium parvum polyclonal antibodies and standardize a Direct Immunofluorescence Assay (DIF) for detecting C. parvum oocysts in fecal samples from calves. In order to obtain anti-C. parvum polyclonal antibodies, two New Zealand rabbits were immunized with a purified solution of C. parvum oocysts and Freund's adjuvant. Purification of the immunoglobulin G (IgG) fraction was performed by means of precipitation in ammonium sulfate and chromatography using a DEAE-cellulose column. The anti-C. parvum polyclonal antibody titer was determined by means of the enzyme-linked immunosorbent assay (ELISA). The rabbit anti-C. parvum IgG fraction was conjugated with fluorescein isothiocyanate and standardization of the DIF was performed using various dilutions of conjugate on slides positive for C. parvum oocysts. The cross-reactivity of the anti-C. parvum conjugate was tested using oocysts of Cryptosporidium serpentis, Cryptosporidium andersoni, Escherichia coli, Eimeria sp., and Candida sp. An anti-C. parvum conjugate was successfully produced, thus allowing standardization of DIF for detection of Cryptosporidium oocysts in fecal samples. Cross-reactivity of anti-C. parvum polyclonal antibodies with C. andersoni and C. serpentis was also observed.

O objetivo deste estudo foi produzir um conjugado contendo anticorpos policlonais anti-Cryptosporidium parvum e padronizar a Reação de Imunofluorescência Direta (RID), para detecção de oocistos de C. parvum em amostras fecais de bezerros. Para produção de anticorpos policlonais anti-C. parvum, dois coelhos da raça Nova Zelândia foram imunizados com uma solução purificada de oocistos de C. parvum e adjuvante de Freund. A purificação da fração de imunoglobulina G (IgG) foi realizada por meio de precipitação em sulfato de amônio e cromatografia em coluna de DEAE celulose. A titulação dos anticorpos policlonais anti-C. parvum foi determinada por meio de ensaio imunoenzimático (ELISA). A fração IgG de coelho anti-C. parvum foi conjugada com isotiocianato de fluoresceína, e a padronização da RID foi feita utilizando-se várias diluições do conjugado, em lâminas positivas para C. parvum. Foi pesquisada também a presença de reatividade cruzada do conjugado anti-C. parvum com C. serpentis, C. andersoni, Escherichia coli, Eimeria sp. e Candida sp.. A produção do conjugado anti-C. parvum foi bem sucedida, sendo possível a padronização da RID para detecção de oocistos em fezes. Foi também observada reatividade cruzada dos anticorpos policlonais anti-C. parvum, com C. andersoni e C. serpentis.

A Hospital-Based Serological Survey of Cryptosporidiosis in the Republic of Korea

The seroprevalence of cryptosporidiosis was examined using patients' sera collected from hospitals located in 4 different areas of the Republic of Korea. ELISA was used to measure antibody titers against Cryptosporidium parvum antigens from a total of 2,394 serum samples, which were collected randomly from patients in local hospitals; 1) Chungbuk National University Hospital, 2) Konkuk University Hospital, 3) local hospitals in Chuncheon, Gangwon-do (province), 4) Jeonnam National University Hospital, from 2002 through 2003. Of the 2,394 samples assayed, 34%, 26%, and 56% were positive for C. parvum-specific IgG, IgM, and IgA antibodies, respectively. Positive IgG titers were most common in sera from Jeonnam National University Hospital, Gwangju, Jeollanam-do, and positive IgM titers were most common in sera from Chungbuk National University Hospital, Cheongju, Chuncheongbuk-do. The seropositivity was positively correlated with age for both the IgG and IgA antibodies but was negatively correlated with age for the IgM antibodies. Western blotting revealed that 92%, 83%, and 77% of sera positive for IgG, IgM, and IgA ELISA reacted with 27-kDa antigens, respectively. These results suggested that infection with Cryptosporidium in hospital patients occurs more commonly than previously reported in the Republic of Korea.

A Hospital-Based Serological Survey of Cryptosporidiosis in the Republic of Korea

The seroprevalence of cryptosporidiosis was examined using patients' sera collected from hospitals located in 4 different areas of the Republic of Korea. ELISA was used to measure antibody titers against Cryptosporidium parvum antigens from a total of 2,394 serum samples, which were collected randomly from patients in local hospitals; 1) Chungbuk National University Hospital, 2) Konkuk University Hospital, 3) local hospitals in Chuncheon, Gangwon-do (province), 4) Jeonnam National University Hospital, from 2002 through 2003. Of the 2,394 samples assayed, 34%, 26%, and 56% were positive for C. parvum-specific IgG, IgM, and IgA antibodies, respectively. Positive IgG titers were most common in sera from Jeonnam National University Hospital, Gwangju, Jeollanam-do, and positive IgM titers were most common in sera from Chungbuk National University Hospital, Cheongju, Chuncheongbuk-do. The seropositivity was positively correlated with age for both the IgG and IgA antibodies but was negatively correlated with age for the IgM antibodies. Western blotting revealed that 92%, 83%, and 77% of sera positive for IgG, IgM, and IgA ELISA reacted with 27-kDa antigens, respectively. These results suggested that infection with Cryptosporidium in hospital patients occurs more commonly than previously reported in the Republic of Korea.

Investigation of cryptosporidiosis by enzyme-linked immunosorbent assay and microscopy in children with diarrhea

To investigate the frequency of cryptosporidiosis by enzyme-linked immunosorbent assay [ELISA] and microscopy and its relationship with diarrhea. The study was prospectively performed in the Parasitology Laboratory and Pediatric Outpatient Clinic of the Research Hospital, Yuzuncu Yil University, Van, Turkey between 2004 and 2006. Stool samples were obtained from a total of 2000 children with diarrhea, 870 females, and 1130 males aging 0-15 years as study group, and 100 children of the same age were randomly selected as a control group. The flotation method was firstly carried out for all stool samples in saturated zinc sulfate solution, then staining process by modified acid-fast staining. All samples were also tested for Cryptosporidium parvum antigen by ELISA. Native-Lugol and trichrome staining were used to identify other intestinal parasites. The antigen was determined in 97 [4.9%] of 2000 children by ELISA, however, the oocysts were only seen in 39 children [1.95%] by microscopy. Cryptosporidium spp. were not detected in the control group either by ELISA or by microscopy. We found a significant [p<0.001] relationship between diarrhea and cryptosporidiosis. Other intestinal parasites were detected in 713 [35.7%] of 2000 diarrheic children. Cryptosporidium spp. antigen searching by ELISA in stool samples should be included for diagnosis of the disease in all hospitals

Role of murine Peyer's patch lymphocytes against primary and challenge infections with Cryptosporidium parvum

In order to determine the role of Peyer's patch lymphocytes (PPL) in self-clearing of Cryptosporidium parvum infection in murine models, changes in PPL subsets, their cytokine expression, and in vitro IgG1 and IgA secretions by PPL were observed in primary- and challenge-infected C57BL/6 mice. In primary-infected mice, the percentages of CD4+ T cells, CD8+ T cells, sIgA+ B cells, IL-2+ T cells, and IFN-gamma+ T cells among the PPL, increased significantly (P 0.05) than those in primaryinfected mice. The results suggest that murine PPL play an important role in self-clearing of primary C. parvum infections through proliferation of CD4+, CD8+, IL-2+, and IFN-gamma+ T cells, and IgG1 and IgA-secreting B cells. In challenge infections, the role of T cells is reduced whereas that of B cells secreting IgA appeared to be continuously important.

Time gap between oocyst shedding and antibody responses in mice infected with Cryptosporidium parvum

We observed the time gap between oocyst shedding and antibody responses in mice (3-week-old C57BL/6J females) infected with Cryptosporidium parvum. Oocyst shedding was verified by modified acid-fast staining. The individually collected mouse sera were assessed for C. parvum IgM and IgG antibodies by enzyme-linked immunosorbent assay from 5 to 25 weeks after infection. The results showed that C. parvum oocysts were shed from day 5 to 51 post-infection (PI). The IgM antibody titers to C. parvum peaked at week 5 PI, whereas the IgG antibody titers achieved maximum levels at week 25 PI. The results revealed that IgM responses to C. parvum infection occurred during the early stage of infection and overlapped with the oocyst shedding period, whereas IgG responses occurred during the late stage and was not correlated with oocyst shedding. Hence, IgM antibody detection may prove helpful for the diagnosis of acute cryptosporidiosis, and IgG antibody detection may prove effective for the detection of past infection and endemicity.

Concurrent response to challenge infection with Cryptosporidium parvum in immunosuppressed C57BL/6N mice

We investigated the response to challenge infection with Cryptosporidium parvum oocysts in immunosuppressed C57BL/6N mice. In the primary infection, fecal oocyst shedding and parasite colonization were greater in immunosuppressed mice than in nonimmunosuppressed mice. Compared with primary infection, challenge infection with C. parvum didn't show any oocyst shedding and parasite colonization. Especially, oocyst shedding and parasite colonization from the mice infected with heatkilled oocysts were not detected. After challenge infection with C. parvum oocysts, however, these mice were shedding small numbers of oocysts and parasite colonization. Except normal control and uninfected groups, the antibody titers of other groups appear similar. Based on the fecal oocyst shedding, parasite colonization of ilea, and antibody titers in the mice, these results suggest that the resistance to challenge infection with C. parvum in immunosuppressed C57BL/6N mice has increased.

Specific bovine antibody response against a new recombinant Cryptosporidium parvum antigen containing 4 zinc-finger motifs

A Cryptosporidium parvum sporozoite and oocyst lambda gt11 cDNA library was screened with a hyperimmune rabbit serum that was developed against insoluble fragments of ultrasonicated oocysts. A clone named Cp22.4.1 encoding a protein of 231 amino acids with 4 zinc-finger domains characterized by a Cys-X2-Cys-X4-His-X4-Cys motif was isolated and characterized. There was a complete match between the sequencing data of the coding region of Cp22.4.1 and the corresponding gene at chromosomal level. Cloning in a pBAD-TOPO-TA expression vector permitted to evaluate the antigenicity of the recombinant His-tagged antigen. This antigen was recognized by 2 out of 5 sera from Cryptosporidium immune calves and not by sera from parasite naive animals.

Antigen incorporation on Cryptosporidium parvum oocyst walls

Cryptosporidium parvum oocysts are the infective stages responsible for transmission and survival of the organism in the environment. In the present work we show that the oocyst wall, far from being a static structure, is able to incorporate antigens by a mechanism involving vesicle fusion with the wall, and the incorporation of the antigen to the outer oocyst wall. Using immunoelectron microscopy we show that the antigen recognized by a monoclonal antibody used for diagnosis of cryptosporidiosis (Merifluor®, Meridian Diagnostic Inc.) could be found associated with vesicles in the space between the sporozoites and the oocysts wall, and incorporated to the outer oocyst wall by an unknown mechanism

Immunofluorescent detection of both giardia lamblia and cryptosporidium parvum using anti-cryptosporidium oocyst antibodies

In the present work, a polyspecific anti-cryptosporidium oocyst antibodies was used for simultaneous detection of both parasites in human stool. Known positive formalinized human stool specimens of Giardia sp. [n = 10], Cryptosporidium sp. [n=7] mixed infection [n=3] and negative specimens [n = 20] were tested using direct fluorescent technique against the developed antibodies. All positive stool samples for Cryptosporidium and 9 out of 10 Giardia samples or each alone showed fluorescence with variable intensities, while no negative sample harbored other parasites had fluorescence. This newly used polyspecific antibodies offer the advantages of screening of a large number of patients, particularly in outbreaks. Additionally, it represents a cheaper alternative for the most sophisticated and costly immunoassay kits using the monoclonal antibodies with more or less the same diagnostic potentials

Identificación de Cryptosporidium en cerdos con enteritis / Identification of Cryptosporidium in pigs with enteritis in Mexico

Se observaron numerosos Cryptosporidium en el borde ciliado de las células epiteliales del intestino delgado, en tres lechones de 10 semanas de edad. Estos hallazgos se asociaron con una severa atrofia de vellosidades y moderada infiltración linfoide en la lámina propia. Además, en todos estos casos hubo una severa neumonía intersticial y linfoproliferativa compatible con una infección por Mycoplasma. Los estudios bacteriológicos fueron negativos a cepas enteropatógenas de Salmonella y Pasteurella. Estos cerdos pertenecían a una piara con mala higiene y sujetos a masivos tratamientos con varios antibióticos. Aunque el principal papel patológico de Cryptosporidium no puede ser atribuido en éste, la infección por este protozoario podría estar involucrada en el desarrollo de las lesiones. La cryptosporidiosis ha sido previamente notificada en becerros en México, pero este constituye el primer informe en cerdos

Incomplete dominance of the low antibody response to Cryptosporidium parvum antigens in mice selected for high and low antibody responsiveness

The humoral antibody response to Cryptosporidium was investigated in mice genetically selected for high (H) and low (L) antibody responsiveness. Groups of 4-5 mice from two different selections, general primary (GP) and general secondary (GS), were studied. Following immunization with Cryptosporidium parvum antigens, the maximum levels of IgG in the HGP, (X ñ SD = 1.13 ñ 0.35, N = 5) and in the HGS (0.42 ñ 0.15, N = 4) lines, and of IgM in the HGP line (0.86 ñ 0.53, N = 5) were significantly higher than those in their L counterparts (0.04 ñ 0.02, N = 5;0.05 ñ 0.02, N = 4 and 0.24 ñ 0.07, N = 5, respectively). These findings were similar to those reported for other immunogens. However, the IgG (0.22 ñ 0.05, N = 4) and the IgM (0.33 ñ 0.08, N = 4) responses to immunization of F1 (LGP x HGP) hybrids indicated an incomplete dominance of the low response, in contrast to the incomplete dominance of the high response described for many other antigens and representing an important exception. In addition, the H, L and F1 mice did not develop detectable infections when inoculated with live Cryptosporidium oocysts, supporting the view that a reduced or zero antibody production itself is not enough to permit the establishment of Cryptosporidium infection in adult mice.