Chemicals immunobiology

Dean, I.H. et al., Assessment of immunobiological effects induced by chemicals, drugs or food additives. II. Studies with cyclophosphamide, Drug Chem. Toxicol., 2, 133, 1979b. 

Before consideration of the available methods, what is known of the immunobiological mechanisms of both forms of chemical allergy will be reviewed briefly. The development of immune responses, including allergic responses, is directed by the activity of CD4+ T helper (Th) cell subpopulations and their cytokine products. Two phenotypes... 

Over the past decade, there have been considerable advances in our understanding of the immunobiological mechanisms that result in the quality of immune response necessary for the induction of chemical respiratory allergy. Experiments designed to characterize immune responses in mice to chemical sensitizers have demonstrated that different classes of chemical allergen stimulate the development of qualitatively discrete immune responses consistent with the selective emergence of functional subpopulations of T lymphocytes [16]. Thus, topical exposure of BALB/c strain mice to chemical contact allergens such as 2,4-dinitrochlorobenzene (DNCB) results in the induction of... 

Ogawa, T., Asai, Y., Sakai, Y., Oikawa, M., Fukase, K., Suda, Y., Kusumoto, S., Tamura T. Endotoxic and immunobiological activities of a chemically synthesized lipid A of Helicobacter pylori strain 206-1. FEMS Immunol Med Microbiol 36 (2003) 1-7. 

Immune systems are responsible for providing organisms with the ability to resist infections from various sources. It is well known that interactions of environmental chemicals with the immune system can both suppress and enhance immune activity (Luster et al., 1988). This means that immune responses have potential as biomarkers of chemical exposure and effect. To date, immune system studies in terrestrial ecosystems have concentrated on earthworms. This is because the immunobiology of this group is well researched and understood. Activities or competencies of the cellular immune system have been measured through a range of parameters, such as ... 

Advances in the understanding of the immunobiology of skin sensitization have led to the establishment of predictive in vivo tests which not only identify sensitizing hazards but also characterize their potency. Recently, appreciation of the underlying biology has also resulted in the development of mechanistically based in vitro alternatives which offer the prospect of the replacement of current in vivo methods. Assays under active validation include the Direct Peptide Reactivity Assay (DPRA), the human Cell Line Activation Test (h-CLAT), and KeratinoSens. None of the methods have a sufficient level of accuracy or freedom from applicability domain limitations to allow them to act as a standalone replacement. Consequently, it will be necessary to consider how to deploy these assays, perhaps in combination and/or in a structured assessment of skin sensitization hazard, to ensure at least the same level of predictive accuracy as the in vivo methods. However, a challenge remains the capacity of these methods to provide potency information on skin-sensitizing chemicals has yet to be assessed. This is an essential requirement for future risk assessment without use of animal models if we are to retain the same level of human health protection that is currently delivered. 

Kimber, 1. and Deaman, R.J., Immunobiology of chemical respiratory sensitization, in Toxicology of Chemical... 

Although relevant immunobiological mechanisms can be envisaged, it must be emphasized that there are currently available no compelling data to indicate that normal exposure to environmental pollutants, other than perhaps tobacco smoke, will induce or enhance allergic sensitization. Nevertheless, the possibility that environmental factors influence susceptibility to chemical respiratory allergens can not be excluded. 

In recent years there have been significant advances in the characterization of immune responses induced by chemical allergens. Despite such progress it must be acknowledged that a consensus regarding the immunobiological mechanisms that, in practice, result in respiratory sensitization has yet to be achieved. At the centre of the debate are questions regarding the importance of IgE and other homocytotropic antibody in the development of sensitization. This and other priority areas for further research are listed below. 

Dean JH, Padarathsingh ML, JerreUs TR. Assessment of immunobiological effects induced by chemicals, dmgs and food additives. I.Tier testing and screening approach. Dmg Chem Toxicol 1979 2(l-2) 5-17. 

Corresponding Author Chitra Mandal—Immunobiology Division, Indian Institute of Chemical Biology, 4 Raja S.C. Mullick Road, jadavpur, Kolkata -700 032, India. 

Sumi Mukhopadhyay nee Bandyopadhyay Immunobiology Division Indian Institute of Chemical Biology Kolkata India... 

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