Anti-S. Typhi Monoclonal Antibodies for Typhoid Fever Rapid Diagnostic Test LFA IVD Development
Salmonella enterica serovar Typhi (S. Typhi) is a host-restricted gram-negative bacterium belonging to the family Enterobacteriaceae. It is the causative agent of typhoid fever (also called enteric fever), a severe systemic illness characterized by sustained high fever, headache, malaise, abdominal pain, and — in severe or untreated cases — intestinal perforation, hemorrhage, and death. S. Typhi is unique among Salmonella serovars in being exclusively human-adapted: humans are the only natural reservoir and source of infection. Transmission occurs via the fecal-oral route — through consumption of water or food contaminated with S. Typhi-containing feces — in settings with inadequate sanitation and water treatment infrastructure. The WHO estimates 11–21 million typhoid cases occur annually, causing 128,000–161,000 deaths worldwide, with the highest burden in South and Southeast Asia (India, Pakistan, Nepal, Bangladesh, Indonesia) and sub-Saharan Africa.
S. Typhi expresses several diagnostically relevant surface structures. The Vi capsular polysaccharide (Vi antigen) is a critical virulence factor and the most typhoid-specific diagnostic target: Vi is expressed only by S. Typhi and the rare S. Paratyphi C serovar, making Vi antigen detection highly specific for typhoid fever. The O9 somatic LPS antigen and H:d flagellar antigen are additional immunogenic markers, though they show cross-reactivity within the broader Salmonella genus. S. Typhi is classified into over 100 genotypes by whole-genome sequencing; clinically the most important emerging concern is extensively drug-resistant (XDR) S. Typhi — defined by resistance to fluoroquinolones, third-generation cephalosporins, and ampicillin — which emerged in Pakistan in 2016 and has spread to multiple countries. XDR typhoid leaves azithromycin and carbapenems as the only reliable treatment options, making rapid and accurate typhoid diagnosis critical to appropriate antibiotic stewardship.
For IVD assay development, typhoid rapid diagnostic tests (RDTs) use either antigen detection (detecting S. Typhi bacterial antigens in patient blood, urine, or stool using anti-S. Typhi monoclonal antibodies in LFA sandwich format) or antibody detection (detecting patient IgM/IgG antibodies against S. Typhi antigens in patient serum). Antigen-based RDTs — which use capture and detection anti-S. Typhi antibodies like Sekbio's typhi-w005 and typhi-w006 — offer the advantage of detecting active infection directly, without requiring the 7–14 day delay for antibody seroconversion. Sekbio provides two characterized anti-S. Typhi monoclonal antibody clones (typhi-w005 and typhi-w006) for IVD manufacturers developing antigen-based typhoid rapid tests targeting the high-burden Africa and Asia markets.
Two anti-Salmonella Typhi monoclonal antibody clones for matched pair LFA development covering capture and detection roles.
| Catalog No. | Target | Type | Application | Storage | MOQ |
|---|---|---|---|---|---|
| typhi-w005 | Anti-S. Typhi (Salmonella Typhi) | Murine mAb IgG | LFA / ELISA — Sandwich | −20°C | 1 mg |
| typhi-w006 | Anti-S. Typhi (Salmonella Typhi) | Murine mAb IgG | LFA / ELISA — Sandwich | −20°C | 1 mg |
Two clones available for matched pair optimization (capture + detection). Contact info@sekbio.com for detailed COA, antigen targeting specifications, ELISA titer data, and matched pair evaluation kits.
Matched antibody pair clones targeting S. Typhi-specific antigens for high-sensitivity, high-specificity typhoid rapid diagnostic test development.
Sekbio's typhi-w005 and typhi-w006 antibodies are raised against S. Typhi-specific antigens, enabling specific typhoid fever diagnosis without cross-reactivity to non-typhoidal Salmonella serovars that commonly co-circulate in the same endemic settings. In Africa and South Asia, where typhoid must be differentiated from malaria, dengue, rickettsial disease, and other febrile illnesses, high diagnostic specificity is paramount for appropriate clinical management. Vi capsular polysaccharide antigen — expressed uniquely by S. Typhi — provides the most typhoid-specific target available for antigen detection. Contact info@sekbio.com for antigen targeting specifications and cross-reactivity data for each clone.
Providing two distinct anti-S. Typhi monoclonal antibody clones (typhi-w005 and typhi-w006) allows IVD manufacturers to optimize LFA performance by testing all four possible matched pair configurations (w005 capture/w006 detector; w006 capture/w005 detector; homo-pair with same clone at different concentrations; combined configurations). Optimal LFA sensitivity and signal-to-noise ratio depends on which clone serves as the colloidal gold-conjugated detector versus the membrane-immobilized capture antibody. Providing paired clones with non-overlapping or complementary epitopes is the foundation of high-performance sandwich LFA assay development. Contact info@sekbio.com for epitope mapping data.
Typhoid fever disproportionately affects low-resource settings in sub-Saharan Africa and South Asia — precisely the markets where rapid, low-cost, point-of-care diagnostic tests are most needed and blood culture infrastructure is unavailable. The emergence of XDR S. Typhi in Pakistan (2016) and its spread to other countries has created urgent demand for reliable typhoid rapid diagnosis to guide appropriate antibiotic selection (azithromycin vs. carbapenem). Sekbio's antibodies are designed for field-deployable LFA tests that can operate without refrigeration at ambient temperatures — a critical requirement for rural health post deployment in sub-Saharan Africa and South Asian primary care settings.
Sekbio's anti-S. Typhi antibodies enable antigen-based rapid tests — detecting S. Typhi bacterial antigens directly in patient samples — rather than antibody-based serology (detecting patient antibodies against S. Typhi). Antigen detection provides earlier diagnosis: S. Typhi antigenemia (bacterial antigen in blood) is detectable in the first week of illness, before adequate patient antibody response has developed. The widely used Widal serology test requires 7–14 days post-infection for seroconversion and has poor sensitivity/specificity in endemic populations (due to background antibodies from prior exposure or vaccination). Antigen-based RDTs built on typhi-w005/w006 represent the next generation of typhoid diagnostics beyond the Widal test.
Anti-S. Typhi antibodies for antigen detection can be applied to multiple patient sample types: blood/serum (for Vi antigenemia detection during bacteremic phase — first week); urine (Vi antigen is excreted in urine in typhoid patients, enabling non-invasive testing); and stool (less commonly used for typhoid antigen detection, but applicable in chronic carrier detection). Multi-sample compatibility enables IVD developers to create both blood-based RDTs (higher sensitivity during acute illness) and urine-based RDTs (non-invasive, home-use potential) from the same antibody pair. Contact info@sekbio.com for sample type optimization guidance.
MOQ 1 mg per clone for R&D. OEM quantities available for typhoid RDT kit manufacturing targeting India, Pakistan, Nigeria, Ethiopia, DRC, Kenya, Bangladesh, Nepal, and other high-burden countries. Sekbio's ISO 13485-certified facility provides quality-documented antibody supply for CE-marked and WHO-prequalified typhoid RDT production. We support regulatory documentation for NMPA (China), EU MDR, WHO prequalification, and national regulatory submissions in target markets. Contact our team or visit our Products page for matched pair evaluation kits and OEM pricing.
Anti-S. Typhi monoclonal antibodies for typhoid antigen rapid tests, outbreak surveillance, XDR typhoid management, and Vi antigenemia detection.
Typhoid fever presents as undifferentiated fever indistinguishable from malaria, dengue, brucellosis, leptospirosis, and other tropical infections without laboratory testing. Blood culture — the gold standard for typhoid diagnosis — requires 3–7 days and centralized laboratory infrastructure. Point-of-care typhoid rapid tests using Sekbio's anti-S. Typhi antibodies deliver results in 10–15 minutes from whole blood, serum, or urine, enabling same-consultation antibiotic prescription in primary care and community health settings in Africa and Asia. Reducing empirical antibiotic use — particularly fluoroquinolone prescription for undiagnosed febrile illness — is critical to slowing the spread of MDR and XDR S. Typhi. WHO's preferred diagnostic algorithm for typhoid includes a rapid antigen test as the first-line point-of-care screening step.
Typhoid outbreaks — particularly XDR typhoid clusters in Pakistan, Zimbabwe, and other countries — require rapid diagnosis capacity to implement case isolation, contact tracing, water chlorination, and emergency vaccination campaigns. Cluster detection using typhoid rapid tests at fever surveillance posts enables real-time outbreak mapping without blood culture infrastructure. Sekbio's S. Typhi antibodies can be incorporated into multiplex rapid tests that simultaneously screen for typhoid alongside malaria, dengue, or other febrile illness pathogens — supporting syndromic fever surveillance programs in high-burden regions. Contact our team to discuss typhoid surveillance-specific antibody performance requirements and appropriate rapid test designs.
Extensively drug-resistant (XDR) S. Typhi — resistant to all oral first-line antibiotics (fluoroquinolones, third-generation cephalosporins, ampicillin, chloramphenicol, trimethoprim-sulfamethoxazole) — was first identified in Hyderabad, Pakistan in 2016 and has caused over 10,000 cases. XDR typhoid is treatable only with azithromycin (mild cases) or intravenous carbapenems (severe cases). Rapid confirmation of typhoid diagnosis using antigen-based RDTs built on typhi-w005/w006 is critical in settings where XDR typhoid is circulating — enabling physicians to prescribe azithromycin (rather than fluoroquinolones) immediately upon positive RDT, without waiting for blood culture sensitivity results. This is a high-impact clinical application of typhoid rapid diagnostics. Visit our Platforms page for development service support.
An estimated 1–6% of typhoid patients become chronic S. Typhi carriers — asymptomatically shedding bacteria in stool for more than 12 months, typically due to gallbladder colonization. Chronic carriers are the primary reservoir sustaining typhoid transmission in endemic communities and can cause point-source outbreaks when employed as food handlers. Screening programs to identify and treat chronic S. Typhi carriers require sensitive antigen or molecular detection of bacteria in stool specimens. Sekbio's anti-S. Typhi antibodies can be applied to stool antigen ELISA for chronic carrier screening in food handler populations and high-risk communities. Contact our team for stool matrix-specific antibody performance data and extraction protocol recommendations.
Technical and commercial questions from IVD R&D engineers developing typhoid fever rapid diagnostic tests.
Typhoid fever is a severe systemic bacterial infection caused by Salmonella Typhi, transmitted via contaminated food and water. WHO estimates 11–21 million cases and 128,000–161,000 deaths annually, predominantly in South Asia and Africa. Clinical diagnosis is unreliable due to symptom overlap with malaria, dengue, and other febrile illnesses. Blood culture (gold standard) requires 3–7 days and laboratory infrastructure. Rapid S. Typhi antigen tests using Sekbio's typhi-w005/w006 antibodies provide 10–15 minute results at point of care — enabling targeted antibiotic therapy and reducing empirical fluoroquinolone use that drives XDR typhoid spread.
Sekbio's S. Typhi antibodies target S. Typhi-specific surface antigens. The Vi capsular polysaccharide (Vi antigen) is the most typhoid-specific target — expressed only by S. Typhi (and the rare S. Paratyphi C), not by non-typhoidal Salmonella serovars or other Enterobacteriaceae. Vi antigen detection provides the highest diagnostic specificity for typhoid diagnosis. Contact info@sekbio.com for detailed antigen specification and cross-reactivity data for each clone.
Yes. typhi-w005 and typhi-w006 are two distinct anti-S. Typhi monoclonal antibody clones provided specifically for matched pair sandwich LFA development. In a standard typhoid antigen LFA: one clone is conjugated to colloidal gold (detector antibody on conjugate pad); the other clone is immobilized on the nitrocellulose membrane (capture antibody on test line). S. Typhi antigen in the sample bridges capture and detector antibodies, generating a visible positive line. Both epitope-matched (for higher antigen-bridging efficiency) and non-overlapping paired configurations can be evaluated. Contact info@sekbio.com for epitope mapping and pair optimization guidance.
Primary: blood/serum (for Vi antigenemia detection in the bacteremic first week of illness — 50–70% positive in blood culture-confirmed cases). Secondary: urine (Vi antigen excreted in urine; non-invasive collection; sensitivity 40–60%); stool (for chronic carrier detection). Blood-based tests provide highest sensitivity during acute illness. Urine tests enable non-invasive, home-use typhoid screening applications. Contact info@sekbio.com for sample type-specific performance data and extraction protocols.
Vi antigen-targeting antibodies are specific to S. Typhi (and very rare S. Paratyphi C). Non-typhoidal Salmonella serovars (S. Typhimurium, S. Enteritidis) do not express Vi polysaccharide — they will not be detected. This Vi-specificity prevents false positives from NTS gastroenteritis, which is far more common than typhoid fever globally. Contact info@sekbio.com for cross-reactivity data for typhi-w005 and typhi-w006 against other Salmonella serovars and common enteric pathogens.
MOQ is 1 mg per clone for R&D. OEM quantities from 10 mg to gram scale for RDT manufacturing. Typhoid rapid tests are needed urgently in Pakistan (XDR typhoid epidemic), India (highest global typhoid burden), Nigeria, Ethiopia, DRC, Kenya, Bangladesh, and Nepal. Sekbio's ISO 13485 certification supports CE marking, WHO prequalification, and NMPA regulatory documentation. Contact info@sekbio.com for matched pair evaluation kits, OEM supply agreements, and typhoid RDT development support.
Request typhi-w005 and typhi-w006 matched pair evaluation kits for LFA sandwich assay optimization and OEM supply discussion.