scholarly journals Host-Pathogen Interactions in Campylobacter Infections: the Host Perspective

2008 ◽  
Vol 21 (3) ◽  
pp. 505-518 ◽  
Author(s):  
Riny Janssen ◽  
Karen A. Krogfelt ◽  
Shaun A. Cawthraw ◽  
Wilfrid van Pelt ◽  
Jaap A. Wagenaar ◽  
...  

SUMMARY Campylobacter is a major cause of acute bacterial diarrhea in humans worldwide. This study was aimed at summarizing the current understanding of host mechanisms involved in the defense against Campylobacter by evaluating data available from three sources: (i) epidemiological observations, (ii) observations of patients, and (iii) experimental observations including observations of animal models and human volunteer studies. Analysis of available data clearly indicates that an effective immune system is crucial for the host defense against Campylobacter infection. Innate, cell-mediated, and humoral immune responses are induced during Campylobacter infection, but the relative importance of these mechanisms in conferring protective immunity against reinfection is unclear. Frequent exposure to Campylobacter does lead to the induction of short-term protection against disease but most probably not against colonization. Recent progress in the development of more suitable animal models for studying Campylobacter infection has opened up possibilities to study the importance of innate and adaptive immunity during infection and in protection against reinfection. In addition, advances in genomics and proteomics technologies will enable more detailed molecular studies. Such studies combined with better integration of host and pathogen research driven by epidemiological findings may truly advance our understanding of Campylobacter infection in humans.

2013 ◽  
Vol 81 (12) ◽  
pp. 4626-4634 ◽  
Author(s):  
Ediane B. Silva ◽  
Andrew Goodyear ◽  
Marjorie D. Sutherland ◽  
Nicole L. Podnecky ◽  
Mercedes Gonzalez-Juarrero ◽  
...  

ABSTRACTInfections with the Gram-negative bacteriumBurkholderia pseudomallei(melioidosis) are associated with high mortality, and there is currently no approved vaccine to prevent the development of melioidosis in humans. Infected patients also do not develop protective immunity to reinfection, and some individuals will develop chronic, subclinical infections withB. pseudomallei. At present, our understanding of what constitutes effective protective immunity againstB. pseudomalleiinfection remains incomplete. Therefore, we conducted a study to elucidate immune correlates of vaccine-induced protective immunity against acuteB. pseudomalleiinfection. BALB/c and C57BL/6 mice were immunized subcutaneously with a highly attenuated, Select Agent-excludedpurMdeletion mutant ofB. pseudomallei(strain Bp82) and then subjected to intranasal challenge with virulentB. pseudomalleistrain 1026b. Immunization with Bp82 generated significant protection from challenge withB. pseudomallei, and protection was associated with a significant reduction in bacterial burden in lungs, liver, and spleen of immunized mice. Humoral immunity was critically important for vaccine-induced protection, as mice lacking B cells were not protected by immunization and serum from Bp82-vaccinated mice could transfer partial protection to nonvaccinated animals. In contrast, vaccine-induced protective immunity was found to be independent of both CD4 and CD8 T cells. Tracking studies demonstrated uptake of the Bp82 vaccine strain predominately by neutrophils in vaccine-draining lymph nodes and by smaller numbers of dendritic cells (DC) and monocytes. We concluded that protection following cutaneous immunization with a live attenuatedBurkholderiavaccine strain was dependent primarily on generation of effective humoral immune responses.


2008 ◽  
Vol 76 (5) ◽  
pp. 2025-2036 ◽  
Author(s):  
Lauriane E. Quenee ◽  
Claire A. Cornelius ◽  
Nancy A. Ciletti ◽  
Derek Elli ◽  
Olaf Schneewind

ABSTRACT Yersinia pestis, the highly virulent agent of plague, is a biological weapon. Strategies that prevent plague have been sought for centuries, and immunization with live, attenuated (nonpigmented) strains or subunit vaccines with F1 (Caf1) antigen is considered effective. We show here that immunization with live, attenuated strains generates plague-protective immunity and humoral immune responses against F1 pilus antigen and LcrV. Y. pestis variants lacking caf1 (F1 pili) are not only fully virulent in animal models of bubonic and pneumonic plague but also break through immune responses generated with live, attenuated strains or F1 subunit vaccines. In contrast, immunization with purified LcrV, a protein at the tip of type III needles, generates protective immunity against the wild-type and the fully virulent caf1 mutant strain, in agreement with the notion that LcrV can elicit vaccine protection against both types of virulent plague strains.


2019 ◽  
Author(s):  
Ria Goswami ◽  
Ashley N. Nelson ◽  
Joshua J. Tu ◽  
Maria Dennis ◽  
Liqi Feng ◽  
...  

ABSTRACTTo achieve long-term viral remission in HIV-infected children, novel strategies beyond early anti-retroviral therapy (ART) will be necessary. Identifying clinical predictors of time to viral rebound upon ART interruption will streamline the development of novel therapeutic strategies and accelerate their evaluation in clinical trials. However, identification of these biomarkers is logistically challenging in infants, due to sampling limitations and potential risks of treatment interruption. To facilitate identification of biomarkers predicting viral rebound, we have developed an infant rhesus macaque (RM) model of oral SHIV.CH505.375H.dCT challenge and analytical treatment interruption (ATI) after short-term ART. We used this model to characterize SHIV replication kinetics and virus-specific immune responses during short-term ART or post-ATI and demonstrated plasma viral rebound in 5 out of 6 (83%) infants. We observed a decline in humoral immune responses and partial dampening of systemic immune activation upon initiation of ART in these infants. Furthermore, we documented that infant and adult macaques have similar SHIV replication and rebound kinetics and equally potent virus-specific humoral immune responses. Finally, we validated our models by confirming a well-established correlate of time to viral rebound, namely pre-ART plasma viral load, as well as identified additional potential humoral immune correlates. Thus, this model of infant ART and viral rebound can be used and further optimized to define biomarkers of viral rebound following long-term ART as well as to pre-clinically assess novel therapies to achieve a pediatric HIV functional cure.IMPORTANCENovel interventions that do not rely on daily adherence to ART are needed to achieve sustained viral remission for perinatally infected children who currently rely on lifelong ART. Considering the risks and expense associated with ART-interruption trials, identification of biomarkers of viral rebound will prioritize promising therapeutic intervention strategies, including anti-HIV Env protein therapeutics. However, comprehensive studies to identify those biomarkers are logistically challenging in human infants, demanding the need for relevant non-human primate models of HIV rebound. In this study, we developed an infant RM model of oral Simian/Human Immunodeficiency virus infection expressing clade C HIV Env, and short-term ART followed by ATI, longitudinally characterizing immune responses to viral infection during ART and post-ATI. Additionally, we compared this infant RM model to an analogous adult RM rebound model and identified virologic and immunologic correlates of time to viral rebound post-ATI.


2006 ◽  
Vol 112 (2) ◽  
pp. 175-185 ◽  
Author(s):  
Yasemin Ataman-Önal ◽  
Séverine Munier ◽  
Arnaud Ganée ◽  
Céline Terrat ◽  
Pierre-Yves Durand ◽  
...  

2014 ◽  
Vol 22 (4) ◽  
pp. 1283-1293 ◽  
Author(s):  
Christopher Marlowe A. Caipang ◽  
Effrosyni Fatira ◽  
Carlo C. Lazado ◽  
Michail Pavlidis

2009 ◽  
Vol 77 (5) ◽  
pp. 1807-1816 ◽  
Author(s):  
Claire A. Cornelius ◽  
Lauriane E. Quenee ◽  
Derek Elli ◽  
Nancy A. Ciletti ◽  
Olaf Schneewind

ABSTRACTYersinia pestisis perhaps the most feared infectious agent due to its ability to cause epidemic outbreaks of plague disease in animals and humans with high mortality. Plague infections elicit strong humoral immune responses against the capsular antigen (fraction 1 [F1]) ofY. pestis, and F1-specific antibodies provide protective immunity. Here we asked whetherY. pestisgenerates mutations that enable bacterial escape from protective immunity and isolated a variant with an IS1541insertion incaf1Aencoding the F1 outer membrane usher. Thecaf1A::IS1541insertion prevented assembly of F1 pili and provided escape from plague immunity via F1-specific antibodies without a reduction in virulence in mouse models of bubonic or pneumonic plague. F1-specific antibodies interfere withY. pestistype III transport of effector proteins into host cells, an inhibitory effect that was overcome by thecaf1A::IS1541insertion. These findings suggest a model in which IS1541insertion intocaf1Aprovides for reversible changes in envelope structure, enablingY. pestisto escape from adaptive immune responses and plague immunity.


mBio ◽  
2019 ◽  
Vol 10 (4) ◽  
Author(s):  
Ria Goswami ◽  
Ashley N. Nelson ◽  
Joshua J. Tu ◽  
Maria Dennis ◽  
Liqi Feng ◽  
...  

ABSTRACT To achieve long-term viral remission in human immunodeficiency virus (HIV)-infected children, novel strategies beyond early antiretroviral therapy (ART) will be necessary. Identifying clinical predictors of the time to viral rebound upon ART interruption will streamline the development of novel therapeutic strategies and accelerate their evaluation in clinical trials. However, identification of these biomarkers is logistically challenging in infants, due to sampling limitations and the potential risks of treatment interruption. To facilitate the identification of biomarkers predicting viral rebound, we have developed an infant rhesus macaque (RM) model of oral simian-human immunodeficiency virus (SHIV) SHIV.CH505.375H.dCT challenge and analytical treatment interruption (ATI) after short-term ART. We used this model to characterize SHIV replication kinetics and virus-specific immune responses during short-term ART or after ATI and demonstrated plasma viral rebound in 5 out of 6 (83%) infants. We observed a decline in humoral immune responses and partial dampening of systemic immune activation upon initiation of ART in these infants. Furthermore, we monitored SHIV replication and rebound kinetics in infant and adult RMs and found that both infants and adults demonstrated equally potent virus-specific humoral immune responses. Finally, we validated our models by confirming a well-established correlate of the time to viral rebound, namely, the pre-ART plasma viral load, as well as identified additional potential humoral immune correlates. Thus, this model of infant ART and viral rebound can be used and further optimized to define biomarkers of viral rebound following long-term ART as well as to preclinically assess novel therapies to achieve a pediatric HIV functional cure. IMPORTANCE Novel interventions that do not rely on daily adherence to ART are needed to achieve sustained viral remission for perinatally infected children, who currently rely on lifelong ART. Considering the risks and expense associated with ART interruption trials, the identification of biomarkers of viral rebound will prioritize promising therapeutic intervention strategies, including anti-HIV Env protein therapeutics. However, comprehensive studies to identify those biomarkers are logistically challenging in human infants, demanding the need for relevant nonhuman primate models of HIV rebound. In this study, we developed an infant RM model of oral infection with simian-human immunodeficiency virus expressing clade C HIV Env and short-term ART followed by ATI, longitudinally characterizing the immune responses to viral infection during ART and after ATI. Additionally, we compared this infant RM model to an analogous adult RM rebound model and identified virologic and immunologic correlates of the time to viral rebound after ATI.


2007 ◽  
Vol 56 (7) ◽  
pp. 888-895 ◽  
Author(s):  
Wei Ling Yu ◽  
Hanhong Dan ◽  
Min Lin

The role of the humoral immune response in protective immunity against listerial infection has been overlooked and is essentially unknown. This study aimed to discover the protein targets of Listeria monocytogenes that elicit an antibody response following infection in a rabbit model. A genomic expression library for L. monocytogenes was constructed and differentially screened to identify genes encoding proteins that reacted with antiserum from rabbits infected with live L. monocytogenes serotype 4b (RαL), but not with that from animals immunized with heat-killed bacteria (RαK). Thirty-one clones expressing proteins that reacted exclusively with RαL were identified and sequenced. Sequence analysis, together with Western blot analysis of the proteins expressed from positive clones, led to the identification of eight L. monocytogenes proteins as targets of humoral immune responses during listerial infection: three internalin members (InlA, InlD and InlC2) and five novel proteins of unknown function (designated IspA, IspB, IspC, IspD and IspE, respectively). Exhibition of humoral immune responses to these proteins in actively infected rabbits but not in animals receiving heat-killed L. monocytogenes suggested that they were induced or significantly upregulated in vivo during infection and thus are important in Listeria pathogenesis. With the exception of antibodies to InlA, this is the first demonstration of antibodies to the other seven proteins in infected hosts. These immunogenic proteins may be useful candidates for elucidation of the role of antibodies in protective immunity in the context of listerial infection, as well as potential targets for serodiagnostic reagents and vaccine and drug development.


2007 ◽  
Vol 73 (11) ◽  
pp. 3765-3767 ◽  
Author(s):  
Stuart W. Naylor ◽  
Allen Flockhart ◽  
Pablo Nart ◽  
David G. E. Smith ◽  
John Huntley ◽  
...  

ABSTRACT Enterohemorrhagic Escherichia coli O157:H7 has a natural reservoir in the intestinal tracts of cattle. Colonization is asymptomatic and transient, but it is not clear if protective immunity is induced. This study demonstrates that prior colonization induces humoral immune responses to bacterial antigens and reduces bacterial shedding after experimental challenge with the homologous strain.


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