Diagnosing infectious and inflammatory diseases with LPS

In Vitro Diagnostic (IVD) tests are becoming major pillars of modern medicine. Doctors and patients rely on them to guide life-or-death medical decisions such as the choice of antibiotics when facing an urgent case of SIRS or Sepsis. 

Recent history shows that their development soars whenever there are emerging new bacterial pathogens, in parallel with antibiotics misuses. Indeed, antibiotics consumption has increased in recent decades due to misdiagnosis caused by low sensitivity of available tests or the complexity of  their implementation leading to delay in the results and in the most appropriate treatment The creation of Point Of Care (POC) tests has become one of the pillars to improve bacterial diagnosis, even in areas where few infrastructures and few qualified staff are present. The goal is to quickly identify the pathogen to facilitate the clinical decision, while being affordable in production costs.

However, the emergence of prevalence resistances slows down their development to target common bacterial antigens. Availability of IVDs for such threats plays a major role in the establishment of an operational coordinated response by public authorities, to contain the spread of pathogenic threats. It gives us a reminder that it is necessary to keep an eye on new strains and to stay at the forefront on bacterial antigen detection.

When it comes to pathogen identification, antibodies are extremely important. LipoPolySaccharides, localized at the surface of certain pathogens, can act as excellent antigens for such purposes. There is a need to assess kit sensitivity to a range of Lipopolysaccharides (LPS), and also to determine their specificity regarding antibody-antigen recognition.

Indeed, the antibodies need to be able to respond with high selectivity and sensitivity to diagnose a specific pathogen in polymicrobial environments and complex mixtures. It also needs to be able to target an antigen common to the many LPS serotypes associated with a pathogen species to avoid false negatives and ensure full detection. In that way, the best therapeutic antibodies can overtake a market on a specific bacterial disease or a bacterial infection.

A good example of the importance of sensitivity could be found in rapid diagnostic tests (RDTs). While such tests are highly interesting for their simplicity of use, quick results, and accessibility to patients, they are lacking sensitivity and reliability in comparison to laboratory tests. 

For example, to diagnose bacterial meningitis, a positive test using meningococcal or pneumococcal antigen antigens on cerebrospinal fluid is excellent at confirming those infections. However, a negative test is insufficient for excluding the infection and discontinuing empiric therapy. Key data on the bacterial culture must be obtained to determine this.

IVD sensitivity to Lipopolysaccharides antigens may be an obstacle course when false positive or negative signals are interfering with the readout. How to know if the interferences come from the test samples and the samples collection method or from the IVD reagent ? 

It is very  difficult to reproduce an optimal medium to detect bacterial antigens and the other components of the matrix which could decrease the sensitivity of the tests. For example, a polymicrobial environment will decrease the recovery rate of the reagent or the latter could interact with the other non-inflammatory molecules. Dilutions of the samples imply sometimes losses of part of the information and can create false positives.  

To answer such questions, highly purified Lipopolysaccharides antigens can make a great difference to standardize the tests and get out from these tricky spots. But you need to rely on well purified antigens to select the best antibodies that will ensure the specificity of your tests.

Studying the implication of lipopolysaccharides in inflammatory diseases and sepsis may be a necessary step to understand their role in a disease or a medical condition. Aside from basic science publications in medical journals, such understanding could define the relevance of a specific polysaccharide or LPS detection in the creation design of a new diagnostic kit.

To help define an antigen candidate, labeled endotoxins can provide a simple and efficient solution to get such understanding in an impact analysis. It is thus possible to study the pathway of LPS in order to elucidate reaction mechanisms or to study translocation phenomena that may be at the origin of diseases. Some recent studies show a very strong relationship between our diet, the nature of our gut microbiome and the passage of harmful LPS through the intestinal barrier (Leaky gut)

To solve such matters, labeled endotoxins can provide a simple and efficient solution  to get such understanding in an impact analysis.