Production and Characterization of Monoclonal Antibodies Against the Major Cysteine Proteinase of Trypanosoma cruzi

In the present study we describe the production and characterization of a panel of monoclonal antibodies (MoAbs) directed against cruzipain (Crz), the major cysteine proteinase from Trypanosoma cruzi . The five MoAbs, BD6, BF2, CG2, CH8, and DC10 were analysed with respect to affinity and specificity. None of the MoAbs cross-reacted with papain, which has regions of high homology with Crz. Treatment of the antigen with periodate did not affect the binding of the MoAbs. suggesting that they bind to the polypeptide moiety of Crz. CH8 recognized a continuous epitope located at the C-terminal extension of the proteinase that appeared to be highly immunogenic. Although the rest of the MoAbs recognized epitopes located in the catalytic domain, the enzymatic activity of Crz was not impaired by the binding of the MoAbs. Characterization of the antibody-binding sites revealed the presence of at least four separate epitopes.     

Novel EphB4 Monoclonal Antibodies Modulate Angiogenesis and Inhibit Tumor Growth

EphB4 receptor tyrosine kinase and its cognate ligand EphrinB2 regulate induction and maturation of newly forming vessels. Inhibition of their interaction arrests angiogenesis, vessel maturation, and pericyte recruitment. In addition, EphB4 is expressed in the vast majority of epithelial cancers and provides a survival advantage to most. Here, we describe two anti-EphB4 monoclonal antibodies that inhibit tumor angiogenesis and tumor growth by two distinct pathways. MAb131 binds to fibronectin-like domain 1 and induces degradation of human EphB4, but not murine EphB4. MAb131 inhibits human endothelial tube formation in vitro and growth of human tumors expressing EphB4 in vivo. In contrast, MAb47 targets fibronectin-like domain 2 of both human and murine EphB4 and does not alter EphB4 receptor levels, but inhibits angiogenesis and growth of both EphB4-positive and EphB4-negative tumors in a mouse s.c. xenograft model. Combination of MAb47 and bevacizumab enhances the antitumor activity and induces tumor regression. Indeed, humanized antibodies hAb47 and hAb131 showed similar affinity for EphB4 and retained efficacy in the inhibition of primary tumor development and experimental metastasis.Angiogenesis is a process of new blood vessel sprouting from pre-existing vessels. This process includes primary capillary sprouting, branching, and remodeling into a mature blood vessel network. In the embryo, angiogenesis is preceded by vasculogenesis and represents one of the earliest processes in organ development.^1,2 In adulthood, angiogenesis is induced at sites of tissue repair, tissue remodeling such as during menstruation, and in diseases constituting enhanced angiogenesis.¹ Angiogenesis is also induced to varying degrees in cancers.¹ Angiogenesis is triggered by protease-mediated degradation of matrix proteins releasing angiogenic factors such as vascular endothelial growth factor (VEGF), epidermal growth factor, and fibroblast growth factor, followed by the migration of endothelial cells to sprout new vessels.^1,3 One critical step in vessel maturation is the interaction between arterial and venous capillaries leading to the fusion and lumen formation across the two cell types. This step is dependent on the interaction between EphB4 receptor tyrosine kinase expressed on venous endothelial cells and the trans-membrane ligand EphrinB2 expressed on arterial endothelial cells.^4,5EphB4 belongs to the Eph family, the largest family of receptor tyrosine kinases. To date, sixteen members of this receptor family have been characterized.^6,7 Eph receptors are divided into two subgroups: EphA members (10 in number) that bind to ligands (EphrinA1-6) that lack trans-membrane domains and localize to the cell membrane via glycosylphosphatidyl inositol linkage. EphB receptors (6 members) bind to ligands (EphrinB1-3) that contain a trans-membrane domain.^6,7 Receptor-ligand interaction leads to dimerization and phosphorylation of both receptor and ligand, resulting in bidirectional signaling. On stimulation with EphrinB2, Eph receptor “forward” signaling is triggered by autophosphorylation of its intracellular tyrosine kinase domain and downstream signaling.^8,9,10 Ephrin-B “reverse” signaling also depends on tyrosine phosphorylation of the Ephrin cytoplasmic region.¹⁰Targeted disruption of the EphB4 gene in mice is embryonically lethal secondary to the failure of blood vessel maturation and capillary arrest.¹¹ EphrinB2 is the only known ligand for EphB4. Targeted disruption of the EphrinB2 gene has a phenotype similar to EphB4 knockout.^5,11 The role of EphB4 in adult vertebrates is not fully understood, in part because of a lack of appropriate conditional knock-out lines. EphB4 and EphrinB2 are induced in newly forming venous and arterial vessels, respectively, and are thus expected to play an important role in adult angiogenesis.^9,12,13 This hypothesis is supported by the observation that the soluble monomeric form of the extracellular domain of EphB4 receptor (sEphB4) that blocks EphrinB2 interaction with its cognate receptors, blocks bidirectional signaling and inhibits angiogenesis at sites of neovascularization in the adult.^14,15,16Human tumor tissue analysis has shown that EphB4 is overexpressed in many tumor types: breast,¹⁷ colon,^18,19,20 bladder,²¹ endometrium,²² head and neck,²³ prostate,^24,25 and ovary.^26,27 EphB4 directly supports tumor cell survival by inhibiting apoptosis in many of these cancers.^{17,18,21,22,23,24,27} Tumor cell–expressed EphB4 also induces angiogenesis by direct interaction with EphrinB2 on tumor vessels.²⁸ In this study, we describe novel EphB4-specific monoclonal antibodies that inhibit formation and maturation of newly forming vessels and inhibit tumor growth in vivo.     

Antibodies Reactive to Trypanosoma cruzi Epimastigotes or Amastigotes Express Different Idiotypic Patterns if from Patients with Different Clinical Forms of Chagas' Disease

Antibodies (Abs) were purified from pooled sera of patients with either indeterminate (IND or I) or cardiac (CARD or C) Chagas' disease, on either epimastigote (EPI or E) or amastigote-enriched (AMAST or A) antigen (Ag) columns and their idiotypic (Id) expression examined. Anti-Id rabbit Abs were raised to the different preparations (E-IdI, E-IdC, A-IdI and A-IdC). Competitive ELISAs using anti-Ids were able to discriminate between IdI and IdC, disregarding Ag reactivity. E-IdI and A-IdI present different inhibitory abilities, as do E-IdC and A-IdC, but IdC always competes with IdI for anti-IdI comparably. In contrast, a 4–8-fold increase of IdI is required to compete in parallel with IdC for anti-IdC. Therefore, Ids from IND patients share only low levels of the Ids that are most characteristic of CARD patients. While some CARD Abs also express Ids in common with IND patients, these studies reveal that CARD Abs express some Ids that are characteristic to only CARD patients, and these Ids are present on Abs purified with either EPI or AMAST.     

Monoclonal antibodies to stages of Trypanosoma cruzi: characterization and use for antigen detection.

Monoclonal antibodies to the amastigote and epimastigote stages of Trypanosoma cruzi were produced and characterized by immunoglobulin class and subclass. Of the 17 monoclonal antibodies, 14 were of the immunoglobulin M (IgM) class and 2 were of the IgG2 and 1 was of the IgG1 subclass of IgG. Five of the monoclonal antibodies recognized the antigens of amastigotes only, two recognized the antigens of epimastigotes only, and ten recognized an antigen(s) common to both stages of T. cruzi. By using an immunofluorescence test with monoclonal antibodies, it was possible to visually localize amastigote- or epimastigote-specific antigens and the antigens common to both. Antigens specific for epimastigotes were noted on the flagellum or in spots over the entire body of the parasite. The antigens common to both amastigotes and epimastigotes were on one of the extremities of the amastigotes and on the region of the flagellar pouch of the epimastigotes. Four of the monoclonal antibodies were capable of detecting T. cruzi antigen in serum from mice infected with the parasite and in the supernatant of infected cell cultures, suggesting that monoclonal antibodies may be useful for antigen isolation and diagnostic methods.     

Immunization Against Experimental Chagas'' Disease by Using Culture Forms of Trypanosoma cruzi Killed with a Solution of Sodium Perchlorate

Protection against infection with virulent blood (trypomastigote) forms of Trypanosoma cruzi was accomplished in mice by immunization with culture (mainly epimastigote) forms killed by treatment with sodium perchlorate. Sodium chloride, used instead of sodium perchlorate, with all other conditions kept the same, failed to kill all the organisms, indicating that the effects of the perchlorate anion were not simply ionic or osmotic, suggesting that they might be chaotropic. A single dose of the immunogen, without adjuvants, was sufficient to significantly protect against the infection. Protection was achieved by either intraperitoneal, intramuscular, or subcutaneous immunization, though the first two routes appeared to be more effective. After challenge, parasitemias were negative in 25, 29, and 17% of the animals immunized intraperitoneally, intramuscularly, and subcutaneously, respectively.     

Monoclonal Antibodies that Specifically Inhibit GM-CSF-and IL-3-Dependent Growth of Human Monocytic Leukemia Cells

Abstract

We describe monoclonal antibodies (mAbs: anti-MaG-1, TGI-1, TGI-5, and TGI-6) that block the proliferation of AML-193 cells in response to GM-CSF or IL-3 and do not affect the proliferation of AML-193 cells in response to G-CSF and IL-2-driven proliferation of Kit 225 cells. However, none of the mAbs tested had any stimulative effect on the proliferation of AML-193 cells. The mAbs (anti-MaG-1, TGI-1, -5, and -6) could inhibit the binding of [¹²⁵I)GM-CSF to AML-193 cells. We were able to purify MaG-1 Ag by anti-MaG-1 affinity chromatography. Thus, the MaG-1 Ag and the Ags recognised by mAbs (TGI-1, -5, and -6) may be associated with the receptor for GM-CSF or IL-3 or a structure close to the receptor for GM-CSF or IL-3.     

前列腺酸性磷酸酶单克隆抗体的制备及临床应用

作者应用纯化的前列腺酸性磷酸酶(PAP)免疫BALB/c小鼠,制备了4株分泌PAP-McAb的杂交瘤细胞株。应用PAP-McAb建立了免疫化学法测定血清中的PAP。318例正常男性,血清中PAP为0～1.6ng/ml。9例病理确诊的前列腺癌。有7例阳性,阳性率为77.8％,而同时应用化学法测定血清中的酸性磷酸酶(ACP),阳性率只有44.4％。     

Susceptibility of radiation chimeras to Trypanosoma cruzi.

Reciprocal bone marrow transfers were performed with C3H/HeJ mice, which are susceptible to infection with the Brazil strain of Trypanosoma cruzi, and resistant F1 (C3H/HeJ X C57BL/6J) mice. Mice reconstituted after lethal irradiation with syngeneic bone marrow displayed the resistance phenotype of the strain used, but neither C3H mice reconstituted with F1 bone marrow cells nor F1 mice reconstituted with C3H bone marrow cells survived challenge. Resistance to T. cruzi appears to be dependent upon factors associated both with host background and with bone marrow-derived cells.     

Genetics of murine resistance to Trypanosoma cruzi.

Resistance to the protozoan parasite Trypanosoma cruzi is governed by multiple genetic factors, including at least one coded for by a locus in or near the major histocompatibility complex of the mouse. The influence of the H-2 locus on resistance was evident when H-2 congenic mice on a strain background of intermediate resistance were challenged or when the survival of H-2 typed F2 mice was followed. The H-2k haplotype of the susceptible C3H/An strain was associated with higher mortality when compared with the H-2b haplotype of the resistant C57BL/10 strain. Genetic studies showed that resistance was a dominant trait and increased with genetic heterozygosity. F1 mice derived from crosses between resistant and susceptible strains, or even between two susceptible strains, were much more resistant than either parent. Crosses between two resistant strains, C57BL/6J and DBA/2J, led to resistant progeny in the F1 and F2 generations; but when recombinant inbred strains derived from these parental strains were challenged, susceptible strains were identified, indicating that different genes were responsible for resistance in the two strains.     

Combined Use of Enzyme-Linked Immunosorbent Assay and Flow Cytometry To Detect Antibodies to Trypanosoma cruzi in Domestic Canines in Texas

Canines may be sentinels and/or reservoirs for human Trypanosoma cruzi exposures. This study adapted a method originally designed for human diagnostics to detect serum immunoglobulin G to T. cruzi in canines. The method combined an enzyme-linked immunosorbent assay (ELISA) for screening and flow cytometry detection of anti-live trypomastigote antibodies (ALTA) for confirmation. The assays were optimized by using known positive and negative control canine sera, and cutoff values were established. The ELISA and ALTA assay easily distinguished between reactive (positive controls) and nonreactive (negative controls) sera and were used to test sera collected in a cross-sectional seroprevalence survey of 356 domestic canines from Harris County, Tex., and the surrounding area. Fifty-three (14.9%) of 356 asymptomatic canines in the survey were positive by ELISA, and 5 (1.4%) were confirmed positive with the ALTA assay, with an additional 4 (1.1%) canines classified as “suspect positive.” Thus, the overall prevalence of T. cruzi antibodies in this population was 2.6%. This is the first U.S. study to use the combination of ELISA and ALTA to detect serum antibodies to T. cruzi and the first report of the prevalence of T. cruzi infection in domestic canines in the Houston, Tex. (Harris County), region. Our results demonstrate that the combination of ELISA and ALTA has been successfully adapted for use in testing canines for serological evidence of T. cruzi infection. Seroprevalence survey results suggest that T. cruzi antibody-positive domestic canines in the peridomestic setting are present in the Houston, Tex., region and further suggest that T. cruzi is enzootic in the region.American trypanosomiasis (Chagas'' disease) is a zoonotic disease caused by the protozoan parasite Trypanosoma cruzi, which is transmitted by hematophagous triatomine (reduviid) insects. The parasite is transmitted when vector feces containing metacyclic trypomastigotes is inoculated into the insect''s bite site through scratching. In animals, transmission may also occur via ingestion of the infected reduviid. The parasite is endemic throughout Latin America and is a major cause of morbidity and mortality in the western hemisphere. According to the World Health Organization, an estimated 16 to 18 million persons are chronically infected with T. cruzi, and up to 50,000 deaths annually result from T. cruzi infection (26-28). The first naturally transmitted case in the United States was reported in Corpus Christi, Tex., in 1955 in a 10-month-old child residing in a triatomine insect-infested house (49, 51). There have since been four indigenous human cases of Chagas'' disease reported in the United States (two in Texas, one in California, and one in Tennessee) (23, 27, 40). Further, serological evidence of T. cruzi infection was found in 6 (2.5%) of 237 residents and in 6 (60%) of 10 dogs from the vicinity of the patient in California (36), and the case in Tennessee was associated with serological evidence of T. cruzi infection in a domestic canine owned by the patient''s family, as well as the finding of an infected reduviid insect within the household (23). Dogs are considered important reservoirs for the transmission of T. cruzi in Latin American countries and in some areas of the United States (7, 20, 21, 35, 43) and serve as natural surveillance sentinels in areas of Latin America where vector control campaigns have been conducted (14, 22).Studies conducted in Texas have found T. cruzi infection in a number of reduviid insects. For example, T. cruzi infection was found in 286 (33.3%) of 859 reduviid insects sampled in southern Texas between 1941 and 1947 (41), and a 1978 survey in the lower Rio Grande Valley of Texas found that 22 (22.6%) of 84 reduviid insects were infected with T. cruzi (12). The persistence of T. cruzi in southern Texas triatomines was recently confirmed when approximately 80% (24 of 31) of the insects from a single residence were found to be infected (9). Seroprevalence studies of wild animals in the southern United States have detected T. cruzi infection in triatomines, coyotes, badgers, raccoons, armadillos, opossums, wood rats, and mice in Texas, California, Louisiana, Oklahoma, Alabama, Maryland, South Carolina, and Georgia (6, 12, 25, 48, 50). Seropositive dogs have been detected in both domestic and stray canine populations in Texas, Oklahoma, Louisiana, Virginia, and other southern states (7, 8, 10, 19, 44). Estimates of seroprevalence in stray-canine populations in the lower Rio Grande Valley of Texas range up to 8.8% (9, 12). T. cruzi-infected dogs from Texas have been found among canine cardiology patients referred to the Texas A&M University College of Veterinary Medicine. Nine fatal cases of canine cardiomyopathy due to American trypanosomiasis from six counties in central Texas were diagnosed between November 1972 and November 1975 (47). Between 1987 and 1996, the Texas Veterinary Medical Diagnostic Laboratory (TVMDL) reported a significant increase (P < 0.0001) in the proportion of seropositive domestic dogs among samples submitted for serological testing for T. cruzi. The proportion of positive cases increased from 1 (1.8%) of 55 samples in 1987 to 12 (17.1%) of 70 samples in 1996 (33). Between 1994 and 1998, samples from 351 domestic dogs from Texas suspected of having Chagas'' disease were submitted to the TVMDL for serological testing for antibodies to T. cruzi; 67 (19.1%) were seropositive (data kindly provided by C. N. Carter, TVMDL, personal communication, 8 May 1999).A number of approaches have been used in the diagnosis of Chagas'' disease, including xenodiagnosis, serological assays, and molecular detection methods. The use of serological assays, including radioimmunoprecipitation assay, direct and indirect hemagglutination, indirect immunofluorescent-antibody (IFA) testing, enzyme-linked immunosorbent assay (ELISA), and various combinations of these tests, has been described for the diagnosis of T. cruzi infection in canines (8, 10, 20, 21, 29, 30, 34, 52, 52). These serological tests have high sensitivity; however, their specificity may be low because of antigenic cross-reactivity with other parasitic species, such as Leishmania spp. Cross-reactivity is especially problematic when assays are based on epimastigote lysates. Intact, fixed T. cruzi epimastigotes are more specific but are still cross-reactive with T. rangeli (39). More recently, the PCR assay has been used to detect T. cruzi DNA in the blood and tissue of infected dogs (2, 10, 31). The PCR assay has shown a variable degree of efficiency in the detection of T. cruzi infection. Avila et al. found the sensitivity of the PCR assay to be 100% compared with serological results in a population of chronic chagasic and non-chagasic human patients (4). However, Junqueira et al. obtained positive PCR assay results in only 59.4% of seropositive human Chagas'' disease patients from a region of Brazil where the disease is endemic. Likewise, Britto et al. found that the PCR assay detected parasite DNA in only 44.7% of a population of human patients who were positive by three separate serological assays (indirect IFA testing, ELISA using the cytosolic epimastigote fraction, and ELISA using recombinant T. cruzi proteins) (11, 24).The use of flow cytometry detection of anti-live trypomastigote antibodies (ALTA) for the diagnosis of Chagas'' disease and detection of parasitologic cure in humans has been described (15, 32). Recently, Araujo et al. compared flow cytometry (ALTA assay) with PCR analysis and other, more conventional diagnostic methods in chronically, experimentally infected canines. In these dogs, at least two serial serum samples and up to nine repeated PCR assays per sample were required to obtain positive PCR results compared to the ALTA assay and ELISA, both of which yielded positive results with all of the samples tested. In contrast, xenodiagnosis and hemoculture were positive in only 11 and 22%, respectively, of the chronically infected canines (2).The purpose of this study was to optimize the (screening) ELISA by using intact, fixed epimastigotes and the flow cytometry (confirmatory) assay by using ALTA for testing canine sera. Secondly, the combination of a screening ELISA and the ALTA confirmatory test was used in a serological study of a domestic canine population in Harris County (Houston), Tex.(This research was conducted in partial fulfillment of the requirements for the degree of Master of Public Health [S. V. Shadomy].)     

EB病毒抗原单克隆抗体的特异性研究

5种EB病毒细胞系通过三步放大间接免疫过氧化物酶方法,检测抗EB病毒抗原的单克隆抗体(McAb)—病毒壳抗原(VCA)、膜抗原(MA),早期抗原(EA)、早期弥漫性抗原(EA—D)、早期限制性抗原(EA—R)、核抗原(EBNA)、核抗原第2型(EBNA—2)及潜在性膜蛋白(LMP)。结果表明McAb、EBNA、EBNA—2和EA有较高特异性,VCA和EA—R有一定特异性,MA、LMP和EA—D未得到预期的特异性反应。     

Use of l-Proline and ATP Production by Trypanosoma cruzi Metacyclic Forms as Requirements for Host Cell Invasion

The process of host cell invasion by Trypanosoma cruzi depends on parasite energy. What source of energy is used for that event is not known. To address this and other questions related to T. cruzi energy requirements and cell invasion, we analyzed metacyclic trypomastigote forms of the phylogenetically distant CL and G strains. For both strains, the nutritional stress experienced by cells starved for 24, 36, or 48 h in phosphate-buffered saline reduced the ATP content and the ability of the parasite to invade HeLa cells proportionally to the starvation time. Inhibition of ATP production by treating parasites with rotenone plus antimycin A also diminished the infectivity. Nutrient depletion did not alter the expression of gp82, the surface molecule that mediates CL strain internalization, but increased the expression of gp90, the negative regulator of cell invasion, in the G strain. When l-proline was given to metacyclic forms starved for 36 h, the ATP levels were restored to those of nonstarved controls for both strains. Glucose had no such effect, although this carbohydrate and l-proline were transported in similar fashions. Recovery of infectivity promoted by l-proline treatment of starved parasites was restricted to the CL strain. The profile of restoration of ATP content and gp82-mediated invasion capacity by l-proline treatment of starved Y-strain parasites was similar to that of the CL strain, whereas the Dm28 and Dm30 strains, whose infectivity is downregulated by gp90, behaved like the G strain. l-Proline was also found to increase the ability of the CL strain to traverse a gastric mucin layer, a property important for the establishment of T. cruzi infection by the oral route. Efficient translocation of parasites through gastric mucin toward the target epithelial cells in the stomach mucosa is an essential requirement for subsequent cell invasion. By relying on these closely associated ATP-driven processes, the metacyclic trypomastigotes effectively accomplish their internalization.Host cell invasion by Trypanosoma cruzi, which is critical for the establishment of infection in mammalian hosts, is a multistep process involving various parasite and host cell molecules that, in a concerted series of events, leads to intracellular Ca²⁺ mobilization in both types of cells (5, 12, 32). The first step of this process, namely, T. cruzi attachment to target cells, requires parasite energy (23). The main source of energy for this event is unknown. Also unknown is whether there are differences in energy requirements among different T. cruzi strains that use distinct mechanisms to enter target cells.Epimastigotes, the proliferative and noninfective developmental forms of T. cruzi, use mainly glucose, l-proline, and l-glutamic acid as carbon sources and to obtain energy through respiration (27). In these parasite forms, the active transport of glucose, l-proline, or l-glutamic acid has been previously demonstrated (2, 24, 25, 29). With regard to l-proline, which is one of the prominent constituents of the hemolymph and tissue fluids of hematophagous insect vectors (1, 6), its uptake by active proline transport systems has been found in epimastigotes (24) and in tissue culture trypomastigotes that correspond to the bloodstream parasites and intracellular epimastigotes and amastigotes (30). Concerning the metacyclic trypomastigotes, which are found in the terminal portions of the digestive tract of triatomine insects and constitute the parasite forms responsible for the initial interaction with host cells, there is no information regarding whether they transport and utilize as an energy source the compounds referred to above.The replicative epimastigotes and the infective metacyclic trypomastigotes may differentially use the resources available in the extracellular milieu for the production of energy required for diverse biological processes. Epimastigotes were shown to transform into metacyclic trypomastigotes within 48 h when l-proline or l-glutamate was added to the medium (15). Another study, using a different T. cruzi strain, showed a high rate of differentiation of epimastigotes to metacyclic forms in a medium composed of artificial triatomine urine supplemented with proline (7). l-Proline was also shown to induce transformation of the intracellular epimastigote-like stage into the trypomastigote stage (30), and it seems to be a main carbon source in the intracellular stages, since its development throughout the intracellular life cycle stages is dependent on the presence of proline and since glucose is not taken up by amastigotes (A. M. Silber, R. R. Tonelli, G. C. Lopes, N. L. Cunha e Silva, A. C. T. Torrecilhas, R. I. Schumacher, W. Colli, and M. J. M. Alves, submitted for publication). The most prominent function of metacyclic forms is to invade host cells, and different T. cruzi strains may use distinct strategies to accomplish that function, as illustrated by studies conducted with the CL and G strains, which belong to two highly divergent genetic subgroups (4). Metacyclic forms of the CL strain engage the stage-specific surface gp82 glycoprotein to bind to host cells and induce actin cytoskeleton disruption and parasite internalization (9). On the other hand, G strain metacyclic forms preferentially use the mucin-like molecules gp35 and gp50 to induce the recruitment of target cell actin to the site of parasite entry (13). In addition, G strain infectivity is influenced by gp90, a metacyclic-stage-specific molecule that downregulates host cell invasion (17). We addressed here issues related to energy requirements in T. cruzi infection by analyzing CL and G strains and, based on the findings with these strains, by extending the study to include other CL-like or G-like parasite strains.     

Monoclonal Antibodies Specific for Sendai Virus I. Production and Characterization of Monoclonal Antibodies

Twelve monoclonal antibodies specific for Sendai virus were prepared by fusing immune LOU rat spleen cells with Y3 or FO myeloma cells. Six antibodies bound the viral glycoprotein HN, and six the viral protein F. Among the six HN-specific monoclonal antibodies, five reacted with the very same epitope and inhibited viral haemagglutination. Two antibodies against the F protein recognized the same epitope, but all the others reacted with different epitopes. All monoclonals were characterized with regard to specificity, biological function, epitope recognition, isotypes, and pI.     

Q热立克次体单克隆抗体的产生及其特性的研究

Q热立克次体存在相变异的现象。随着相变异的出现,Q热立克次体的生物学特性、理化性质和抗原性等方面均有变化。这种变化的发生与Q热立克次体的表面结构和抗原组分的改变有密切关系。为了在分子水平上研究Q热立克次体,阐明相变异的机制或研究Q热立克次体的致病性、血清免疫学