How Innovative Methods for Cytokine Quantification Advance our Understanding of Human Health and Disease

Cytokines and their functions

Cytokines are protein molecules that play an important role in intercellular signaling and are involved in numerous physiological and pathological processes. They are most widely known for regulating inflammation and thus modulating the function of the immune system. However, cytokines have also been implicated in metabolism, cell proliferation and differentiation, apoptosis, tissue repair, and chemotaxis.1,2 Moreover, cytokines have found application in several therapeutic areas, including for the treatment of cancer, rheumatoid arthritis, and multiple sclerosis. There are more than 100 cytokines, including interleukins, interferons, chemokines, lymphokines, monokines, and colony-stimulating factors. Whereas some cytokines, such as IL-6, IL-1β, and TNF-α, promote inflammation, others, such as IL-10 and IL-4, inhibit it. 

Cytokine storm and its role in the pathogenesis of the coronavirus disease 2019 (COVID-19)

Under physiological conditions, the production of cytokines is regulated by the immune system. However, in some infectious, inflammatory, and autoimmune disorders, the regulatory function of the immune system is disrupted, and cytokine overproduction occurs. The release of too many pro-inflammatory cytokines during a too short period of time has been designated as cytokine storm and is damaging to cells. A cytokine storm may occur in conjunction with certain infectious, inflammatory, and autoimmune disorders. Recently, the involvement of cytokine storm in the pathophysiology of COVID-19 and its association with poor prognosis have been demonstrated. Therefore, researchers strive to determine the most critical cytokines involved in COVID-19-associated cytokine storm and the optimal strategies for their therapeutic targeting.3 Moreover, due to the significance of cytokines for human health and disease, it is crucial to develop precise, reliable, and easy-to-use methods for their determination. 

Enzyme-linked immunosorbent assay (ELISA) for reliable and efficient cytokine quantification

Cytokines can be determined employing different techniques, one of the most established among which is ELISA. This method relies on the use of a specific antibody targeting and binding the cytokine of interest and subsequent cytokine quantification using a standard curve.4 ELISAs are widely utilized for protein quantification due to their quantitative nature, high sensitivity and specificity, and relative ease of use. Moreover, ELISAs can determine proteins in a variety of sample types. Traditionally, ELISAs have been established for the detection of single markers; however, multiplex ELISAs are also being developed to capture the complexity of protein, including cytokine, regulation.  

Signosis offers versatile ELISA solutions for cytokine quantification

Signosis has developed highly sensitive and specific ELISAs for the quantification of cytokines in various sample types. Our assays are provided as kits, strips, and plates for the detection of individual cytokines, functionally related cytokine groups, and a wide range of cytokines, respectively. Notably, we have developed assays for the detection of cytokines in human, rat, or mouse samples. 

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Our individual ELISA kits are characterized by their efficiency, flexibility, specificity, cost-effectiveness, and ease of use. To facilitate research into the complex processes involving cytokines, we also offer cytokine ELISA strips enabling the measurement of up to eight cytokines that are functionally related or have been implicated in specific biological processes, such as obesity, oxidative stress, angiogenesis, inflammation, neuroinflammation, and endoplasmic reticulum stress. Finally, to gain insight into the complexity of cytokine function, we offer cytokine ELISA plate arrays that allow the simultaneous determination of up to 48 cytokines for two human samples.

Ultrasensitive DNA-linked immunoassays

Despite their high sensitivity, standard ELISAs may not be able to reliably detect and quantify proteins with extremely low concentrations. Therefore, researchers are working on the development of optimized, ultra-sensitive assays. For example, immune-polymerase chain reaction (immuno-PCR), a method combining the use of an antibody and PCR amplification, increases the assay sensitivity 100-fold. However, the use of immune-PCR is also associated with challenges, including high background and low signal/background ratio due to exponential amplification. To solve this challenge, Signosis has developed a cutting-edge product, UltraSensi DNA-linked immunoassay, that uses close proximity ligation technology. It is based on the conjugation of two DNA oligos with a pair of target-specific antibodies, bringing the oligos in close proximity and enabling their ligation when the antibodies simultaneously bind to the target protein. The ligated DNA is then extended and linearly amplified. Finally, a streptavidin-HRP reaction in a rapid plate hybridization assay enables cytokine detection and quantification. The ultrasensitive DNA-linked immunoassays have a detection limit as low as 0.1 fg/ml with over 6-log detection range. In addition to their ultrasensitivity, our DNA-linked immunoassays are characterized by reduced non-specific signals and a wide dynamic range.

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Innovative and versatile solutions for cytokine quantification

Cytokines play a critical role in processes related to human health and disease, including COVID-19. Thus, the development of optimized methods for cytokine quantification are crucial to gain further insight in cytokine function. Signosis ELISAs and ultrasensitive DNA-linked immunoassays provide innovative, versatile, and flexible solutions for cytokine quantification. 

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To learn more about Signosis comprehensive solutions for cytokine quantification, review our cytokine ELISAs product page!

Resources

1. Arango Duque G, Descoteaux A. Macrophage cytokines: involvement in immunity and infectious diseases. Front Immunol. 2014;5:491. doi: 10.3389/fimmu.2014.00491.

1. Foster JR. The functions of cytokines and their uses in toxicology. Int J Exp Pathol. 2001;82(3):171-92. doi: 10.1046/j.1365-2613.2001.iep0082-0171-x.

1. Yang L, Xie X, Tu Z, Fu J, Xu D, Zhou Y. The signal pathways and treatment of cytokine storm in COVID-19. Signal Transduct Target Ther. 2021;6(1):255. doi: 10.1038/s41392-021-00679-0.

1. Chiswick EL, Duffy E, Japp B, Remick D. Detection and quantification of cytokines and other biomarkers. Methods Mol Biol. 2012;844:15-30. doi: 10.1007/978-1-61779-527-5_2.