Strain-specific Monoclonal Antibodies Research Articles

Monoclonal antibodies to Chlamydia psittaci: characteristics and antigenic analysis.

Twenty-seven hybrid cell lines producing monoclonal antibodies to Chlamydia psittaci were prepared by fusion of the mouse myeloma cells with spleen lymphocytes of mice immunized with C.psittaci pigeon or budgerigar strain. Reactions of these monoclonal antibodies were examined with five strains of C.psittaci and two of C.trachomatis serovars L2 and J by enzyme-linked immunosorbent assay, the microimmunofluorescent test and the complement fixation test. According to the reaction patterns to eight chlamydial strains, fifteen antibodies to a pigeon strain, P-1041, were divided into three groups: three genus-specific, eight subspecies-specific and four strain-specific antibodies. Twelve antibodies to a budgerigar strain, Izawa, were also tested to eight chlamydial strains and divided into two groups: two genus-specific and ten subspecies-specific antibodies. Physicochemical properties of the antigens recognized by different monoclonal antibodies were examined by KIO4, pronase and heat treatments and by the immuno-blotting technique. Most genus-specific antibodies recognized the KIO4-sensitive antigen, which was a pronase-resistant and heat-stable component of about 10, 000 daltons. Subspecies- and strain-specific monoclonal antibodies recognized the antigens, which were pronase-sensitive and heat-labile components of about 40, O00 or 90, O0O daltons.

Trypanosoma cruzi strain-specific monoclonal antibodies: identification of Colombian strain flagellates in the insect vector

Spleen cells from mice immunized with insect-derived Trypanosoma cruzi metacyclic trypomastigotes were used to obtain Colombian strain-specific monoclonal antibodies. At least 4 different strain-specific antigens were recognized by the monoclonal antibodies on epimastigotes or metacyclic trypomastigotes. There was no reactivity with other stages of Colombian strain T. cruzi, nor with any stage of 15 other T. cruzi strains or isolates, nor with 22 other Trypanosomatidae. One of the monoclonal antibodies was used to identify, by indirect immunofluorescence, Colombian strain flagellates in cryostat sections or glass-slide smears of the insect vector's intestine.

Newcastle disease vaccine (La Sota) strain specific monoclonal antibody

Newcastle disease virus vaccine strain (La Sota) specific monoclonal antibody (La-1) was produced by immunizing mice with isolated glycoproteins of strain La Sota. This antibody was recognized only in the ELISA test in which it bound exclusively to La Sota strain out of a range of over 300 lentogenic, mesogenic and velogenic strains examined.

Caracterização de cepas de plasmodium falciparum do Estado de Rondônia, Brasil, utilizando microtestes de sensibilidade aos antimaláricos, tipificação enzimática e anticorpos monoclonais

Nove amostras de Plasmodium falciparum foram coletadas de migrantes infectados no Estado de Rondônia. Estas amostras foram mantidas em cultivo para caracterização por tipificação enzimática em acetato de celulose, sensibilidade á cloroquina, amodiaquina, mefloquina e quinino e análise da diversidade antigê-nica através de anticorpos monoclonais específicos. Os resultados obtidos mostraram variação entre todas as amostras estudadas: encontrou-se resistência crescente à cloroquina, resistência intermediária à amodiaquina e quinino e sensibilidade a baixos níveis de mefloquina; apenas dois isolados mostraram sensibilidade a todas as drogas. A tipificação enzimática mostrou presença de parasitas GPI 1 e 2 e ADA 1 e 2, enquanto que para PEP e LDH todas as amostras foram do tipo 1. Sorotipagem com anticorpos monoclonais PSA mostrou presença de três sorotipos diferentes (II, III e IV). Estes resultados mostraram: a) variação entre as amostras para os marcadores analisados; b) nesta região, para o pequeno número de amostras analisadas, não foram observadas diferenças significativas ou novos tipos de parasitas.

Immunological properties of Rickettsia tsutsugamushi, Kawasaki strain, isolated from a patient in Kyushu.

Nine isolates of Rickettsia tsutsugamushi were obtained from patients with Tsutsugamushi disease (scrub typhus) in Miyazaki Prefecture in Kyushu. Immunological analyses of these patients' sera and the isolates were performed by indirect immunofluorescence, indirect immunoperoxidase or immunoblotting techniques. In the analysis of reactions of the patients' sera with the prototype strains Gilliam, Karp, and Kato and with the isolates, sera from two patients, including Kawasaki, showed similar profiles and cross-reaction with the two isolates recovered from the corresponding patients, but reacted only weakly with the prototype strains. With guinea pig polyclonal antibodies against the isolate and prototype strains, Kawasaki strain showed some degree of cross-reaction with Gilliam strain but not with either Karp or Kato strain, nor with Shimokoshi strain which is known to be different antigenically from the prototype strains. Additionally, strain-specific murine monoclonal antibodies against Gilliam, Karp, and Kato strains did not react at all with Kawasaki strain. These results suggest that the Kawasaki strain may be different antigenically from the prototype strains and Shimokoshi strain. The finding two strains of the same antigenic type (Kawasaki) among only nine isolates suggests the presence of Kawasaki-type rickettsiae in Miyazaki Prefecture. Shimokoshi strain also did not react with these strain-specific monoclonal antibodies, suggesting that strains of R. tsutsugamushi antigenically distinct from the prototype strains, such as Kawasaki and Shimokoshi strains, may easily be recognized by their nonreactivity with these monoclonal antibodies.

Concurrent Circulation of Antigenically Distinct Strains of Respiratory Syncytial Virus During Community Outbreaks

Respiratory syncytial virus (RSV) is considered to be of a single serotype. Antigenic variants are detectable both by neutralization and monoclonal antibodies and have been divided into two broad categories, groups 1 and 2. Group 2 isolates have been considered to be uncommon. We used indirect immunofluorescence with strain-specific monoclonal antibodies to study RSV isolates from hospitalized infants in the greater Boston area. Of 223 RSV isolates recovered over a five-month period in 1983-1984, 125 (56%) were group 1, 92 (41%) were group 2, and 6 (3%) were of an intermediate character. Among 181 community-acquired RSV isolates, both temporal and geographic clustering was observed: group 1 isolates were common from January through March and predominated in central Boston; group 2 isolates were found principally in February and were acquired in outlying, particularly northern, areas. Strain-specific differences were not found with respect to sex, age, or clinical findings. An analysis of 82 RSV isolates from the 1981-1982 season showed 75 (91%) group 1 isolates and 7 (9%) group 2 isolates. We conclude that at least two antigenically distinct groups of RSV isolates may circulate concurrently in the community and that the prevalence of group 2 isolates appears greater than previously suspected.

Quantification of respiratory syncytial virus polypeptides in nasal secretions by monoclonal antibodies.

An indirect enzyme-linked immunosorbent assay (ELISA) which uses monoclonal antibody as solid-phase immunosorbent was developed to measure specific polypeptides of respiratory syncytial virus (RSV). The assay was used to examine 43 nasopharyngeal (NP) aspirates from RSV-positive infants that had been examined previously for RSV by culture, direct immunofluorescence, and polyclonal antibody ELISA. Frozen NP aspirates were serially diluted and examined for the 66K mol. wt. fusion glycoprotein (F), the 84K large surface glycoprotein (G) and the 41K nucleoprotein (N) by monoclonal capture ELISA. F protein was detected in all 43 specimens, G protein was detectable in 20 (47%) and N protein in 22 (51%) of 43 NP aspirates. In specimens with detectable G and N proteins, F was detected by endpoint titration at approximately tenfold greater dilutions than either G or N. In 19 sequential NP aspirates from five patients with RSV infection, F was present in higher titre throughout infection. In 20 cases, matching cell culture isolates were examined by immunofluorescence with strain-specific monoclonal antibodies. Three of 20 isolates showed strain-specific differences by their lack of reaction with anti-G monoclonal antibody. Titration of the 20 cell culture isolates by monoclonal antibody capture ELISA showed the relative amount of F and N proteins to be equal in all cases, whereas levels of G protein tended to be slightly lower. Reconstruction experiments with NP aspirates demonstrated that degradation of F and N proteins did not occur in NP aspirates, but that G protein antigenicity appeared to be affected by nasal secretions. When compared with cell culture-grown material, nasal secretions contained abundant F protein but a surprisingly low concentration of N protein.

Genetic Characterization of Poliovirus Isolates in Canada, 1962–1981

From 1962 to 1981, 629 poliovirus strains of human and sewage origin were assayed for genetic markers in the kinetic serum neutralization ( KSN ) and temperature marker (rct) tests. The KSN test proved to be most dependable: 97% of strains tested could be classified as either vaccine-like (VL) or non-vaccine-like ( NVL ). All but two of the 18 virus strains whose classification was inconclusive in the KSN test were further characterized by micro serum neutralization assay. The correlation between the results of the rct and KSN marker tests was not satisfactory for the characterization of poliovirus types 1 and 3. Numerous type 1 virus strains were analyzed with strain-specific monoclonal antibodies for antigenic markers and were examined in polyacrylamide gel electrophoreses for viral proteins. Whereas greater than 90% of poliovirus types 2 and 3 were found to be VL in the KSN test, 40% of type 1 isolates were classified as NVL . The latter were detected not only in the epidemics of 1962 and 1978-1979 caused by type 1 poliovirus but also were present in endemic form in the late 1960s and 1970s in various provinces. In contrast, no NVL type 2 strains were detected in any specimen, and the last type 3 NVL strains were demonstrated in 1963-1964. Thus only type 1 poliovirus appears to be endemic in Canada.

Clonal diversity in a single isolate of the malaria parasite Plasmodium falciparum

Clones of an isolate of Plasmodium falciparum from Mae Sod (Thailand) were prepared by a dilution procedure. Some of the parasite cultures thus obtained have been typed for the following characters: (i) electrophoretic variants of three enzymes; (ii) susceptibility to chloroquine and pyrimethamine; (iii) antigen diversities recognized by ten strain-specific monoclonal antibodies; (iv) presence or absence of knobs on infected erythrocytes and (v) two-dimensional PAGE variants of seven proteins. Amongst the clones there was variation involving each of these five characters. At least seven different types of clones were found in ten cultures produced by dilution. The amount of phenotypic variation within a single isolate has thus been shown to be surprisingly great. Variations in drug susceptibility and antigens are considered to be particularly important in view of their relevance to anti-malarial treatments.