THE SEROLOGICAL RELATIONSHIPS OF THE RICKETTSIAE OF EPIDEMIC AND MURINE TYPHUS

1946 ◽  
Vol 24e (2) ◽  
pp. 84-103 ◽  
Author(s):  
James Craigie ◽  
Dennis W. Watson ◽  
Eina M. Clark ◽  
M. Elizabeth Malcomson

The complement-fixing antibodies present in epidemic and murine typhus immune sera can be differentiated by quantitative absorption tests. The neutralizing antibodies that participate in the Giroud reaction can be differentiated by quantitative inhibition tests.Epidemic and murine typhus immune sera contain two kinds of complement-fixing antibodies and also two kinds of neutralizing antibodies. The antigens that react with these antibodies differ in specificity and thermal resistance. Cross reactions between epidemic and murine rickettsiae are due to the presence of similar heat stable antigens in the two types. Type specific sera may be obtained by absorbing immune serum with either (a) rickettsiae of heterologous type or (b) heated rickettsiae of homologous type. The specific antibodies react only with the heat labile antigens of the homologous type of rickettsiae.Mice may be actively immunized against the toxic factors of murine and epidemic rickettsiae. The immunity produced by small doses of vaccine is type specific and dependent on the presence of heat labile antigen in the vaccine.

1939 ◽  
Vol 69 (1) ◽  
pp. 31-48 ◽  
Author(s):  
Thomas M. Rivers ◽  
S. M. Ward ◽  
Joseph E. Smadel

The soluble antigen of myxoma is a heat-labile protein which has an isoelectric point near pH 4.5 and is precipitated from half saturated solutions of ammonium sulfate. It can be partially purified by methods of differential precipitation based on variations in the pH and electrolyte concentration. Rabbits receiving the labile, soluble substance of myxoma develop homologous precipitins and their serum agglutinates elementary bodies of myxoma, provided the dermal pulp from which the bodies are obtained contains the soluble substance; neutralizing antibodies do not appear, however, and the animals are not resistant to infection with the virus of myxoma. Elementary bodies of myxoma appear to have a heat-stable agglutinogen that operates when brought in contact with serum from animals recovered from myxoma, but little, if at all, when in contact with anti-soluble substance serum.


2014 ◽  
Vol 82 (5) ◽  
pp. 1823-1832 ◽  
Author(s):  
Xiaosai Ruan ◽  
Donald C. Robertson ◽  
James P. Nataro ◽  
John D. Clements ◽  
Weiping Zhang

ABSTRACTA long-standing challenge in developing vaccines against enterotoxigenicEscherichia coli(ETEC), the most common bacteria causing diarrhea in children of developing countries and travelers to these countries, is to protect against heat-stable toxin type Ib (STa or hSTa). STa and heat-labile toxin (LT) are virulence determinants in ETEC diarrhea. LT antigens are often used in vaccine development, but STa has not been included because of its poor immunogenicity and potent toxicity. Toxic STa is not safe for vaccines, but only STa possessing toxicity is believed to be able to induce neutralizing antibodies. However, recent studies demonstrated that nontoxic STa derivatives (toxoids), after being fused to an LT protein, induced neutralizing antibodies and suggested that different STa toxoids fused to an LT protein might exhibit different STa antigenic propensity. In this study, we selected 14 STa toxoids from a mini-STa toxoid library based on toxicity reduction and reactivity to anti-native STa antibodies, and genetically fused each toxoid to a monomeric double mutant LT (dmLT) peptide for 14 STa-toxoid-dmLT toxoid fusions. These toxoid fusions were used to immunize mice and were characterized for induction of anti-STa antibody response. The results showed that different STa toxoids (in fusions) varied greatly in anti-STa antigenicity. Among them, STaN12S, STaN12T, and STaA14Hwere the top toxoids in inducing anti-STa antibodies.In vitroneutralization assays indicated that antibodies induced by the 3×STaN12S-dmLT fusion antigen exhibited the greatest neutralizing activity against STa toxin. These results suggested 3×STaN12S-dmLT is a preferred fusion antigen to induce an anti-STa antibody response and provided long-awaited information for effective ETEC vaccine development.


Author(s):  
Gerhard Dobler

• TBE appears with non-characteristic clinical symptoms, which cannot be distinguished from oth-er forms of viral encephalitis or other diseases. • Cerebrospinal fluid and neuro-imaging may give some evidence of TBE, but ultimately cannot confirm the diagnosis. • Thus, proving the diagnosis “TBE” necessarily requires confirmation of TBEV-infection by detec-tion of the virus or by demonstration of specific antibodies from serum and/or cerebrospinal fluid. • During the phase of clinic symptoms from the CNS, the TBEV can only rarely be detected in the cerebrospinal fluid of patients. • Most routinely used serological tests for diagnosing TBE (ELISA, HI, IFA) show cross reactions resulting from either Infection with other flaviviruses or with other flavivirus vaccines.


TBE appears with non-characteristic clinical symptoms, which cannot be distinguished from other forms of viral encephalitis or other diseases. Cerebrospinal fluid and neuro-imaging may give some evidence of TBE, but ultimately cannot confirm the diagnosis. Thus, proving the diagnosis “TBE” necessarily requires confirmation of TBEV-infection by detection of the virus or by demonstration of specific antibodies from serum and/or cerebrospinal fluid. During the phase of clinic symptoms from the CNS, the TBEV can only rarely be detected in the cerebrospinal fluid of patients. Most routinely used serological tests for diagnosing TBE (ELISA, HI, IFA) show cross reactions resulting from either infection with other flaviviruses or with other flavivirus vaccines.


2007 ◽  
Vol 82 (3) ◽  
pp. 1332-1338 ◽  
Author(s):  
Jay W. Hooper ◽  
Anthony M. Ferro ◽  
Victoria Wahl-Jensen

ABSTRACT Hantavirus pulmonary syndrome (HPS) is a highly pathogenic disease (40% case fatality rate) carried by rodents chronically infected with certain viruses within the genus Hantavirus of the family Bunyaviridae. The primary mode of transmission to humans is thought to be inhalation of excreta from infected rodents; however, ingestion of contaminated material and rodent bites are also possible modes of transmission. Person-to-person transmission of HPS caused by one species of hantavirus, Andes virus (ANDV), has been reported. Previously, we reported that ANDV injected intramuscularly causes a disease in Syrian hamsters that closely resembles HPS in humans. Here we tested whether ANDV was lethal in hamsters when it was administered by routes that more accurately model the most common routes of human infection, i.e., the subcutaneous, intranasal, and intragastric routes. We discovered that ANDV was lethal by all three routes. Remarkably, even at very low doses, ANDV was highly pathogenic when it was introduced by the mucosal routes (50% lethal dose [LD50], ∼100 PFU). We performed passive transfer experiments to test the capacity of neutralizing antibodies to protect against lethal intranasal challenge. The neutralizing antibodies used in these experiments were produced in rabbits vaccinated by electroporation with a previously described ANDV M gene-based DNA vaccine, pWRG/AND-M. Hamsters that were administered immune serum on days −1 and +5 relative to challenge were protected against intranasal challenge (21 LD50). These findings demonstrate the utility of using the ANDV hamster model to study transmission across mucosal barriers and provide evidence that neutralizing antibodies produced by DNA vaccine technology can be used to protect against challenge by the respiratory route.


1994 ◽  
Vol 180 (6) ◽  
pp. 2147-2153 ◽  
Author(s):  
M Pizza ◽  
M R Fontana ◽  
M M Giuliani ◽  
M Domenighini ◽  
C Magagnoli ◽  
...  

Escherichia coli enterotoxin (LT) and the homologous cholera toxin (CT) are A-B toxins that cause travelers' diarrhea and cholera, respectively. So far, experimental live and killed vaccines against these diseases have been developed using only the nontoxic B portion of these toxins. The enzymatically active A subunit has not been used because it is responsible for the toxicity and it is reported to induce a negligible titer of toxin neutralizing antibodies. We used site-directed mutagenesis to inactivate the ADP-ribosyltransferase activity of the A subunit and obtained nontoxic derivatives of LT that elicited a good titer of neutralizing antibodies recognizing the A subunit. These LT mutants and equivalent mutants of CT may be used to improve live and killed vaccines against cholera and enterotoxinogenic E. coli.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jean-François Bruxelle ◽  
Tess Kirilenko ◽  
Nino Trattnig ◽  
Yiqiu Yang ◽  
Matteo Cattin ◽  
...  

AbstractThe occurrence of oligomannose-specific broadly neutralizing antibodies (bnAbs) has spurred efforts to develop immunogens that can elicit similar antibodies. Here, we report on the antigenicity and immunogenicity of a CRM197-conjugate of a previously reported oligomannose mimetic. Oligomannose-specific bnAbs that are less dependent on interactions with the HIV envelope protein sequence showed strong binding to the glycoconjugates, with affinities approximating those reported for their cognate epitope. The glycoconjugate is also recognized by inferred germline precursors of oligomannose-specific bnAbs, albeit with the expected low avidity, supporting its potential as an immunogen. Immunization of human-antibody transgenic mice revealed that only a TLR4-stimulating adjuvant formulation resulted in antibodies able to bind a panel of recombinant HIV trimers. These antibodies bound at relatively modest levels, possibly explaining their inability to neutralize HIV infectivity. Nevertheless, these findings contribute further to understanding conditions for eliciting HIV-cross-reactive oligomannose-specific antibodies and inform on next steps for improving on the elicited response.


1998 ◽  
Vol 61 (2) ◽  
pp. 141-145 ◽  
Author(s):  
HAU-YANG TSEN ◽  
LIANG-ZHAO JIAN ◽  
WAN-RONG CHI

Enterotoxigenic Escherichia coli (ETEC) strains which produce heat labile and/or heat stable toxins (LT and ST) may cause diarrhea in humans and farm animals. Using PCR primers specific for the LT I and ST II genes, a multiplex PCR system which allows detection of LT I- and ST II-producing ETEC strains was developed. When skim milk was used for a PCR assay, it was found that if target cells in the sample were precultured in MacConkey broth for 8 h prior to PCR as few as 100 cells per ml of the sample could be detected. Without the preculture step, 104 CFU of target cells per 0.2 g of porcine stool specimen were required to generate visible PCR products. The multiplex PCR System can be used for rapid testing of fecal specimens, food and possibly environmental samples for the presence of ETEC strains.


2003 ◽  
Vol 10 (3) ◽  
pp. 388-393 ◽  
Author(s):  
Francois-Xavier Mbopi-Kéou ◽  
Laurent Bélec ◽  
Julie Dalessio ◽  
Jérôme Legoff ◽  
Gérard Grésenguet ◽  
...  

ABSTRACT Antibodies to herpes simplex virus type 1 (HSV-1) and HSV-2 of the immunoglobulin G (IgG) and IgA isotypes were detected in the cervicovaginal secretions (CVS) of 77 HSV-1- and HSV-2-seropositive but clinically asymptomatic African women by type-specific enhanced chemiluminescence Western blotting (ECL-WB). Of the 77 subjects, 34 were HIV negative, shedding HSV-2 DNA in their genital secretions; 20 were HIV positive, shedding HSV-2 DNA; and 23 were HIV negative, not shedding HSV-2 DNA. HSV-specific IgG was detected in CVS of nearly 70% of the women studied. HSV-specific IgA was found in CVS of 50% of the women studied. The distribution of CVS HSV-specific antibodies to each HSV type was highly heterogeneous, with a slight predominance of detectable IgG to HSV-1 (59%) over IgG to HSV-2 (41%), whereas the frequency of detectable IgA to HSV-1 (39%) was similar to that of IgA to HSV-2 (36%). The presence of detectable HSV-specific antibodies was inversely associated with HSV-2 DNA genital asymptomatic shedding but was not affected by HIV seropositivity. In addition, 13 of 77 (17%) CVS samples showed neutralizing activity against HSV-2, as assessed by an HSV-2 in vitro infectivity reduction assay. Neutralizing activity in CVS was associated with the presence of IgG and/or IgA antibodies to HSV-1 and/or to HSV-2 by ECL-WB. Among women whose CVS showed HSV-2-neutralizing activity, the specific activity of HSV-specific neutralizing antibodies was substantially (fivefold) higher in HSV-2 DNA shedders than in nonshedders. In conclusion, HSV-specific antibodies are frequently detected in CVS of asymptomatic African women seropositive for HSV-1 and HSV-2. A subset of these women had functional neutralizing activity against HSV-2 in their CVS. The origin of these antibodies and their role in HSV-2 disease of the female genital tract remain to be determined.


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