High susceptibility of partridges ( Perdix perdix ) to toxoplasmosis compared with other gallinaceous birds

Partridges ( Perdix perdix ), chukars ( Alectoris chukar ), wild guineafowl ( Numida meleagris ), wild turkeys ( Meleagris gallopavo ) and chickens ( Gallus domesticus ) were inoculated per os with 103 or 105 Toxoplasma gondii oocysts (K7 strain). Two of five partridges fed 103 oocysts and six of eight partridges fed 105 oocysts died between day 6 and 16 post-inoculation (p.i.); no clinical symptoms were observed in surviving birds. Antibodies to T. gondii were detected in the birds by the indirect fluorescence antibody test (IFAT) first on day 7 p.i. On days 14, 21 and 28 p.i. (end of the experiment), antibodies were found in all partridges, chukars, guineafowl and turkeys. In chickens, IFAT antibodies were first detected on day 14 p.i., and all chickens were serologically positive on days 21 and 28 p.i. Bioassay in mice revealed T. gondii in the brain, liver, spleen, heart and leg muscles of all partridges and chukars. Enteritis was the most striking lesion in partridges that died. Results indicated that partridges are highly susceptible to toxoplasmosis, while chukars, wild guineafowl and turkeys seem to be less susceptible. Chickens are highly resistant to T. gondii infections.     

Experimental toxoplasmosis in chukar partridges(Alectoris graeca)

Thirty battery-hatched chukar partridges (Alectorts graeca) were inoculated orally with oocysts of the ME 49 or the GT-1 strain of Toxoplasma gondii. All six chukars given 10,000 GT-1 strain oocysts died or were euthanized between postinoculation day (p.i.d.) 3 and 6. Fifteen of 24 chukars given 10,000, 1000, 100 or 10 ME 49 strain oocysts died or were euthanized between p.i.d. 6 and 14. Nine chukars that were not ill by p.i.d. 14 remained clinically normal until euthanized in good health p.i.d. 47 and 67; T. gondii was found by bioassay in mice inoculated with tissues of these nine chukars. From the tissues of five chukars bioassayed individually in mice, T. gondii was isolated from brains of four of four tested, and from the hearts and skeletal muscles of five, and livers of three of five chukars tested. Major lesions in chukars that died or those euthanized when ill were enteritis, splenic necrosis, myocarditis and encephalitis. Myocarditis and encephalitis persisted in chukars examined p.i.d. 47, 53 and 67. All chukars examined p.i.d. 10 developed anti-T. gondii antibodies. Anti-T. gondii antibodies detected in the modified agglutination test were higher than those in latex and haemagglutination tests. The Sabin-Feld-man dye test did not detect T. gondii antibodies in sera of chukars. The ME 49 strain of T.gondii was more pathogenic to chukars weighing >/= 300 g than to the 25 g Swiss Webster mice.     

Experimental toxoplasmosis in house sparrows (Passer domesticus)

A total of 31 house sparrows (Passer domesticus) were divided into five groups of six to seven birds. Birds were infected per os with 1, 10, 102, 103 and 104 oocysts of Toxoplasma gondii of the K1 strain, respectively. When the general health, production of antibodies against T. gondii and isolation positivity of the sparrows were examined in weeks 3, 7 and 12 post-infection (p.i.), no clinical signs of toxoplasmosis were observed. Seroprevalences ascertained in weeks 3, 7, and 12 p.i. were 64% (18 positive/28 tested), 95% (21/22) and 70% (7/10) when tested by indirect immunofluorescence (titre 20); 54% (15/28), 59% (13/22) and 70% (7/10) when tested by the latex agglutination test (titre 20); and 59% (4/7), 0% (0/12) and 20% (2/10) when tested by the Sabin Feldman dye test (titre 4), respectively. T. gondii was re-isolated from 45% (13/29) infected sparrows. House sparrows were found to exhibit some resistance to the K1 strain of T. gondii after oocyst infection, and the results suggest that sparrows may not be a significant source of environmental infection.     

Absence of a role for natural killer cells in the control of acute infection by Toxoplasma gondii oocysts.

The active phase of primary and challenge oral infections of Toxoplasma gondii was investigated with respect to natural killer (NK) activity against YAC-1 tumour cell targets in vitro and serum interferon (IFN) titres. Primary (non-lethal) oral infection of BALB/c mice with Me49 oocysts resulted in a rapid increase of serum IFN titres, followed by augmented NK activity. NK levels became depressed, rising again by 15 days after infection to normal levels, again preceded by elevated IFN titres. In challenge infections NK was not augmented and IFN titres rose only if a high dose of oocysts was given. IFN activity was pH2-labile in all cases and considered to be due to IFN-gamma. Cold target inhibition studies indicated that T. gondii did not bind to NK cells. A bioassay for the effects of NK cells on T. gondii tachyzoites was developed and there was no evidence of killing in vitro by cells with NK function; T. gondii survived better when cultured with NK cells than when cultured alone. Studies using C57BL/6bg/bg,bg/+ and +/+ mice showed that there was no difference in mean time to death after administration of a lethal ME49 oocyst infection by mouth. Cytotoxicity against YAC-1 in both spleen and mesenteric lymph node (MLN) cell populations was highly augmented in bg/+ and +/+, but not in bg/bg mice. Genetic deficiency of NK activity had no effect on survival of mice after infection. Therefore NK has at best a minimal role to play in protection during the acute phase of Toxoplasma infection.     

Incidence of Toxoplasma gondii in populations of domestic birds in the Czech republic

The prevalence of Toxoplasma gondii in the domestic fowl was studied in the Strakonice district in southern Bohemia (Czechoslovakia) between 1981 and 1990. The presence of antibodies and T. gondii cysts was ascertained by means of Sabin-Feldman dye tests and isolation assays, respectively. Of 3338 samples of chicken serum from 13 small backyard operations, antibodies were detected in 5.1% of cases. T. gondii cysts were found in two of 10 chickens examined. A total of 1120 chickens from a commercial farm was tested and antibodies were found in 0.01% of them. Isolation assays were made on 1097 chickens and T. gondii cysts were found in 0.36% of them. In small backyard operations, tests for antibodies were made on 28 guinea-fowl (negative), 297 ducks (1.7% positive) and 32 geese (15.6% positive).     

Serological reactivity against cyst and tachyzoite antigens of Toxoplasma gondii determined by FAST-ELISA.

AIMS--To obtain quantitative data on the human serological response to Toxoplasma gondii tachyzoite and bradyzoite antigens. METHODS--Serum samples from 30 patients who had positive antibody titres against T gondii and from 14 who were seronegative, together with sequential serum samples from four infected individuals, were screened by FAST-ELISA. RESULTS--Serum samples from the 30 seropositive patients showed high IgG and IgM titres against the T gondii tachyzoite antigen but very low responses to cyst antigen. This result was borne out in sequential serum samples from patients with toxoplasmosis. CONCLUSION--Antibody recognition of the cystic stage of T gondii is low, implying that either this stage is poorly immunogenic or that the antigen load is low.     

Rat model of congenital toxoplasmosis.

A rat model of congenital toxoplasmosis is described for the study of protective immunity and chemotherapy during pregnancy. Six Sprague-Dawley 7- to 15-day gestational rats were inoculated orally (three rats, trial A) or subcutaneously (three rats, trial B) with 10,000 infective oocysts of the CT-1 strain of Toxoplasma gondii. The tissues of rat pups born from these rats were bioassayed for T. gondii infection. T. gondii was recovered from 30 of 33 (90.9%, trial B) and 23 of 28 (82.17%, trial A) rat pups bioassayed at 1 to 134 days of age. Two 10- to 14-day gestational pregnant rats were inoculated subcutaneously (trial C) with 10,000 infective bradyzoites from tissue cysts; 10 of 23 (43.8%) of the newborn pups were infected with T. gondii. Congenital infection occurred only when rats were infected during pregnancy. None of three rats in trial A that had given birth to congenitally infected rat pups produced congenitally infected rat pups during the second pregnancy.     

Humoral response to defined epitopes of tubercle bacilli in adult pulmonary and child tuberculosis

In order to investigate the humoral response to tuberculosis in different categories of patients, serum antibody levels to six epitopes ofMycobacterium tuberculosis in adult pulmonary and child tuberculosis were determined. Serum antibody titres were determined by competitive inhibition with radio-labelled murine monoclonal antibodies in 67 adults and 85 children with tuberculosis and in 79 age-matched controls. BCG vaccination (n=39) and self-healed tuberculosis (n=11) in adults gave rise to higher antibody titres to TB68, TB23 and TB72 epitopes (all p<0.003) when compared to non-vaccinated controls (n=18). TB68 titres were higher (p=0.006) in self-healed than in vaccinated adults. Adult sputum-negative patients (n=15) had higher titres to TB71 (p=0.015) and ML34 (p=0.02) epitopes compared to BCG-vaccinated healthy controls, while sputum-positive patients (n=41) had higher titres to all epitopes tested (all p<10^–4). The diagnostic sensitivity, with a 95 % specificity, was best with the combination of probes TB23, TB68, TB72 for sputum-positive (85 %) and TB78, ML34 (53 %) for sputum-negative patients. Antibody titres in children with tuberculosis were lower than in adult patients; diagnostic sensitivity in histologically or microbiologically proven cases (n=18) was only 44 %, while that in mediastinal lymphadenitis (n=67) was 13.5 %. This study suggests that the magnitude and specificity of the humoral response to tubercle bacilli varies with site and severity of infection; the implications for pathogenesis or protective immunity are discussed.     

The effect of surgical immunomodulation on liver inflammation and clearance of DHBV infection

The key to developing a therapeutic vaccine for chronic hepadnavirus infection lies in the characteristics of the host-immune response which leads to clearance of acute infection. Groups of 28-day-old ducks which had been surgically bursectomized (n = 10) or thymectomized (n = 13) on the day of hatch or were untreated (n = 21) were inoculated with 10(9) viral genome equivalents (vge) DHBV, then bled twice a week, and euthanased 40 days later. Serum and liver were tested for DHBV DNA and total leukocytes and peripheral blood mononuclear cells (PBMCs) counted. Liver and spleen sections were either stained with hematoxylin and eosin, and graded for inflammation or stained with peroxidase-labeled anti-human CD3 antibody and examined for T lymphocyte distribution. PBMC counts were similar in all groups. DHBV infection combined with bursectomy increased significantly, while thymectomy decreased significantly the total leukocyte count. The spleen and liver bursectomy increased T lymphocyte number while B cells were decreased. Converse changes were observed in thymectomized ducks. Histological evidence of hepatitis was present in infected control and bursectomized ducks but not in the uninfected control or infected thymectomized ducks. In control animals, DHBV challenge caused viremia in 17 and persistent infection in 11 (56%). Fewer thymectomized ducks (3/13, 23%) and significantly more (100%) bursectomized ducks remained persistently infected (P < 0.001). Unexpectedly, bursectomy led to persistence of infection while clearance of infection occurred normally in thymectomized ducks despite decreased T lymphocyte numbers. This suggests that clearance requires T and B lymphocyte collaboration.     

Colostral immunity in piglets from sows vaccinated with inactivated Aujeszky disease virus vaccine

Neutralizing antibodies against ADV were transmitted from sows, vaccinated with inactivated ADV adjuvanted with DEAE dextran, to their offspring via colostrum. The suckling piglets were protected by colostral immunity against contact infection with ADV at week 1 p.p., however, they were not protected against i.n. infection (10(8) TCD50). At 2 and 3 weeks p.p. all the piglets were protected against both contact infection and i.n. infection. At 4 weeks p.p. 50 per cent of the litter were protected against i.n. infection, in spite of very low antibody titres (1:2--1:4). The colostral antibodies did not interfere with active antibody response when the piglets were vaccinated with the inactivated vaccine from 2 weeks p.p. onward. Lymphocytes from suckling piglets of a vaccinated sow showed in vitro reactivity (enhanced 3H-thymidine incorporation) against ADV and BHK antigen, both contained in the vaccine used for the immunization of the sow.     

Disease association of antibodies to human and mycobacterial hsp70 and hsp60 stress proteins.

Structural homology between microbial and human stress proteins has been postulated to be a basis for autoimmunization in chronic inflammatory diseases. Therefore, we estimated by ELISA titration the antibody levels to mycobacterial (M) and human (H) recombinant hsp70 and M-hsp65 heat-shock proteins in sera of patients with Crohn's disease (n = 29), ulcerative colitis (n = 20) and nontuberculous mycobacterial disease of the lungs (n = 20). Antibodies to H-hsp60, separated by two-dimensional gel electrophoresis, were tested in six sera of each group of patients. In Crohn's disease, antibody titres to the M-hsp65 antigen without detectable H-hsp60 binding were significantly elevated in 52% of the patients. In contrast titres to both M-hsp70 and H-hsp70 were demonstrable and correlated, but increased over control values only in four (14%) patients. The antibody pattern in ulcerative colitis was found to be quite different: anti-H-hsp60 binding was demonstrable in most patients, although anti-M-hsp65 titres were not elevated. Furthermore, 25% of patients had significantly elevated titres to M-hsp70, but not to H-hsp70. In non-tuberculous mycobacterial pulmonary disease, about 50% of patients had elevated titres to both hsp65 and hsp71 mycobacterial antigens but not to the corresponding human proteins; patients with Mycobacterium xenopi infection had the highest titres in this group. These results demonstrate the existence of distinct disease-associated patterns in the human antibody response to stress protein antigens. However, these data are not sufficient to imply sensitization with mycobacteria in patients with inflammatory bowel diseases, since certain epitopes of heat-shock proteins are shared by several bacterial genera.     

An enzyme-linked immunosorbent assay (ELISA) for the detection of chlamydial antibody in duck sera

An enzyme-linked immunosorbent assay (ELISA) for the detection of chlamydial antibody in duck sera is described. The assay was used to test sera from a flock of domestic Pekin ducks infected with Chlamydia psittaci, and sera from wildfowl (Mallard). Sera from 63% of the domestic birds and 75% of the wildfowl exhibited chlamydial antibody titres of >/= 1/32, indicative of current or past chlamydial infection. There was a good correlation between the results obtained with the ELISA and those obtained by a micro-immunofluorescence test. The application of the ELISA to large scale screening of flocks is suggested.     

Results of a serological survey made in France (Vendeé region) in domestic ducks

The sera of domestic ducks were examined for antibodies to several infectious agents of palmipeds during the winter of 1982 in the abattoirs in la Vendée, an important region of duck production in the West of France. The performance of each batch and their antecedents was also studied. In Barbary ducks and crossbred ducks (from male wild ducks and female domestic ducks), antibodies were found to the virus of egg drop syndrome 16 (EDS 76), to Newcastle disease virus (NDV), to duck hepatitis virus and to chlamydia psittici. In Nantais ducks (resulting from a cross between Khaki Campbell and Pekin ducks), antibodies were detected against EDS 76 virus, duck hepatitis virus and chlamydia. The frequency and levels of antibodies varied between types or strains of ducks. About 50% of the Barbary ducks had high levels of antibodies to EDS 76 virus, whereas 70 to 80% of crossbred and Nantais ducks had these antibodies but at very low levels. Virtually 100% of Barbary ducks had high levels of antibodies against Derzsy's disease virus whereas only 10% of the batches of crossbred ducks had antibodies at varying levels. The proportion of batches with antibodies against NDV was higher in crossbred ducks (25%) than in Barbary ducks (2%) and the titres were low. Antibodies to duck hepatitis virus, when present, were of a high titre irrespective of type or strain of duck. Infection by chlamydia was suspected in 3% of lots of Barbary ducks, in 33% of lots of crossbred ducks, and in 3.7% of lots of Nantais ducks. These findings are discussed and considered in relation to breeding history and performance of the flocks. The EDS 76 virus could in certain circumstances cause weight loss in male Barbary ducks. These epidemiological observations need to be confirmed experimentally.     

Complete protection against lethal Toxoplasma gondii infection in mice immunized with a plasmid encoding the SAG1 gene

Infection with the protozoan parasite Toxoplasma gondii is transmitted to humans from infected animals by tissue cysts and oocysts excreted by cats. Immunization with inactivated parasites or recombinant proteins has at best shown partial protection. We constructed a plasmid expressing the SAG1 surface antigen of T. gondii, p1tPASAG1, and showed that animals immunized with the plasmid produce anti-SAG1 antibodies which recognize the native SAG1. Mice immunized with p1tPASAG1 showed 80 to 100% protection against challenge with the non-cyst-producing, virulent RH isolate, compared to an 80% mortality in mice immunized with empty plasmid, which is the greatest efficacy of any vaccine against T. gondii produced so far. The SAG1 molecule was analyzed for potential cytotoxic T-lymphocyte (CTL) epitopes, and four peptides with the best fit were synthesized. The ability of the peptides to stimulate gamma interferon production by CD8(+) T cells from p1tPASAG1-immunized mice was tested in an ELISPOT assay, and one new CTL epitope was identified. Adoptive transfer of CD8(+) T cells from p1tPASAG1-immunized to na?ve mice showed partial protection. In conclusion, DNA vaccination with p1tPASAG1 gave effective protection in mice against T. gondii infection and the protection could be adoptively transferred by purified CD8(+) T cells.     

Antibodies to Epstein-Barr virus-induced early antigens in blood donors

IgG class antibodies to the early antigen complex (EA; D + R components) of the Epstein-Barr virus (EBV) were found by indirect immunofluorescence in titres greater than or equal to 1:10 in 196 (49.4%) out of 397 blood donors and titres greater than or equal to 1:20 in 84 (21.2%) of these subjects. Anti-EA titres of greater than or equal to 1:2560 were detected in 6 sera, anti-EA(D) only in 17 donors (4.3%). Additional EBV-specific antibody tests were performed in sera with anti-EA-IgG titres of greater than or equal to 1:20 (n = 84), including IgM class antibodies to virus capsid antigen (anti-VCA-IgM). Specific IgM revealed active EBV infection in 12 blood donors. There was no correlation between the presence of anti-VCA-IgM and the magnitude of anti-EA-IgG titres. Therefore, it seems to be impossible to define the threshold titre for EA antibodies indicating active EBV infection. For this purpose probably a titre increase should be demonstrated in paired sera.     

Dropped egg production in ducks associated with adenovirus infection

Six thousand laying ducks were kept on a large-scale farm, half of which were home-reared ducks, and the other half were imported birds. At the beginning of the laying period 70% of the ducks reared on the farm possessed EDS antibodies in titres of 1:32 to 512, whereas only 20% of the imported ducks were found to possess haemagglutination inhibition (HI) antibodies in titres of 1:16 to 1:32. When the ducks reached the peak of egg production, a severe diarrhoea was observed and egg production decreased by 50% and 10% in the imported ducks and the home-reared ducks, respectively. The decrease in egg production lasted only for 1 week, and production then returned to a normal level. Shell-less and soft-shelled eggs were not recorded, but sometimes misshapen eggs were found. From small intestinal contents of ducks with diarrhoea a haemagglutinating virus identical with McFerran's adenovirus 127 was isolated. HI antibodies appeared in 100% of the convalescent sera. Hatching losses exceeded those observed in previous year by 20%. It may be presumed that the drop in egg production of laying ducks was caused by EDS virus infection.     

Infection dynamics and clinical features of cryptosporidiosis in SCID mice.

Cryptosporidial infections in severe combined immune deficient (SCID) mice produce a chronic disease state which in the later stages leads to extraintestinal involvement and hepatic dysfunction. To further characterize the infection dynamics in this model and monitor the changes in the hepatic system, a dose titration of the oocyst inoculum was performed and alkaline phosphatase levels in the sera were assayed. Ten SCID mice per dose were inoculated with 10(3), 10(4), 10(5), 10(6), or 10(7) oocysts. Oocyst shedding in the feces was quantified by microscopic enumeration. Mice inoculated with 10(6) oocysts and those inoculated with 10(7) oocysts demonstrated similar oocyst shedding patterns, but the 10(7)-oocyst group exhibited signs of distress (e.g., weight loss and icterus) earlier. The intensity of the infection increased markedly approximately 14 days postinoculation (p.i.) and continued to increase steadily over the next 6 weeks. Inoculation with lower oocyst doses produced a delay in patency (e.g., it occurred 7 days later with the 10(5)-oocyst inoculum and 14 days later with the 10(4)-oocyst inoculum). Mean serum alkaline phosphatase levels in the 10(7)-oocyst group were more than twice control values at 5 weeks p.i. and continued to increase over the next 8 weeks. Oocyst doses and alkaline phosphatase levels were positively correlated with hepatobiliary colonization (r = 0.71) and liver necrosis (r = 0.65) at 13 weeks p.i. A strong positive correlation between hepatobiliary colonization and liver necrosis at 13 weeks p.i. (r = 0.87) was observed.     

E-rosette forming cells and humoral antibody titres in humans after vaccination with three different inactivated influenza virus vaccines A/USSR/92/77 (H1N1)

The number of E-rosette forming cells and the serum haemagglutination inhibition (HI) antibody titres were examined in 37 volunteers immediately before and 14, 28, 35 and 63 days after immunization with three inactivated influenza virus vaccines A/USSR/92/77 (H1N1)--NIB 6 and in 11 non-vaccinated controls. From the former, 10 volunteers were immunized with 1000 haemagglutinin (HA) IU per dose, 11 volunteers with the NIB 6 adsorbate vaccine (340 HA IU/dose) and 16 volunteers with a bivalent vaccine composed of 180 HA IU/dose NIB 6 and 180 HA IU/dose of influenza virus A/Bangkok X-73 (H3N2). The percentage of E-rosette forming cells was decreased in all vaccinated volunteers 14 days after vaccination; later on the values reached normal level of non-vaccinated controls or of subjects before vaccination. The number of E-rosette forming cells was in correlation with the applied virus vaccine dose, i.e. for the 1000 HA IU/dose: 29.95 +/- 11.74%, p less than 0.001 and for the 340 HA IU/dose: 47.75 +/- 11.15%, p less than 0.005; however, after administration of 180 HA IU/dose of NIB 6 in the bivalent vaccine, the value 58.65 +/- 11.5% was not significantly decreased in comparison to non-vaccinated donors. The serum HI antibody titres reached the highest level 14 days after vaccination and remained constant during the next 6 weeks. There was a correlation between decreased E-rosette values and increased serum antibody titres (p less than 0.05). The current study indicates that the number of E-rosette forming cells may serve as a further laboratory criterion for controlling the effect of inactivated influenza virus vaccines on the immune system of man.     

Transient hypogonadotrophic hypogonadism in males with acute toxoplasmosis: suppressive effect of interleukin-1 beta on the secretion of GnRH

BACKGROUND: In September 2002, an outbreak of toxoplasmosis was noted in a male boarding high school on the Aegean coast of Turkey. We have focused our efforts to investigate the sex hormones in this population. METHODS: Blood samples were collected from 40 male patients, 17-18 years old, who also had positive titres of antibody to Toxoplasma gondii. Serum FSH, LH, free testosterone (FT), total testosterone (TT), interferon-gamma (IFN-gamma), interleukin-1beta (IL-1beta) and macrophage-inflammatory protein-1alpha (MIP-1alpha) concentrations were measured in all patients and 20 control subjects. Initially, the patients were divided on the basis of the levels of sex hormones into the following groups: patients who had normal sex hormone levels (n = 31) as group A and patients with low sex hormone levels (n = 9) as group B. RESULTS: IL-1beta levels were found to be higher in group B patients than group A. The levels of IL-1beta correlated significantly in a negative manner with FSH, LH, FT and TT in all patients with acute toxoplasmosis (n = 40). CONCLUSIONS: Acute toxoplasma infection may cause temporary hypogonadotrophic gonadal insufficiency regardless of the course of the disease.     

抗弓形虫P30单克隆抗体的制备及其抗虫作用观察

制备抗弓形虫天然P30、重组P30的单克隆抗体(mAb),并研究它们对虫体的影响,为弓形虫病诊断及保护性抗原鉴定奠定基础。采用弓形虫天然P30、重组P30及全虫抗原(对照)分别免疫BALB/c小鼠,取免疫小鼠脾细胞与SP2/0骨髓瘤细胞融合,筛选稳定分泌高滴度mAb的杂交瘤细胞株。用ELISA法测定mAb亚类和效价;通过SDS-PAGE和West-ern blot进行特异性鉴定;Giemsa染色观察杂交瘤细胞的染色体数目;利用扫描电镜及间接荧光抗体试验(IFAT)观察mAb对弓形虫的杀伤作用及其靶抗原定位。结果表明,筛选出2株(2B3、1H6)特异性较好、能稳定分泌mAb的杂交瘤细胞株。Western blot结果显示,2B3、1H6产生的mAb与弓形虫全抗原的阳性反应带均在30 000 Mr处;mAb亚类均属IgM,其效价(ELISA)分别为:2B3 1∶102 400、1H6 1∶51 200;2株细胞的染色体数均在100条以上。电镜观察与mAb作用后的弓形虫虫体聚集、肿胀,膜变厚,表面出现缺口和空洞,甚至虫体变形、破碎。抗弓形虫天然P30的mAb能识别重组体pET-30a-P30的表达蛋白。成功制备了抗弓形虫天然P30、重组P30的mAb,可进一步用于弓形虫病诊断及保护性抗原鉴定研究。