Have a specific question about your LBP project? Click below and let’s get started.
List Labs currently has over 3300 citations with more being added every month! Within our citations page, we provide the ability to search and sort from over 100 cataloged items that are offered here.
We are honored to supply researchers worldwide with highly purified bacterial toxins that can potentially be instrumental in helping to change the world!
In this post, we’ve gathered all of our current citations for our Diphtheria product group. Please use these citations as a reference and resource for your potentially life-changing work!
Diphtheria Toxin & CRM
Corynebacterium diphtheriae is a Gram-positive, bacterium that infects epithelial cells of the upper respiratory tract and produces diphtheria toxin. Diphtheria toxin is proteolytically cleaved forming a two-part toxin, held together by a disulfide bridge. The amino-terminal carries the toxin’s enzymatic activity, capable of ADP-ribosylation and inactivation of translation elongation factor 2 (EF-2). The carboxy-terminal domain binds to specific host receptors, the heparin-binding EGF-like growth factor (HB-EGF) on human epithelial cells, and translocates the catalytic domain into the cell. After binding to the cell receptor, the diphtheria toxin is taken up by endocytosis, the pH of the endocytic vesicle drops, and the translocation region of the toxin helps guide the catalytic domain into the host cytoplasm where it is released. Within the cytoplasm, the diphtheria toxin catalytic domain ADP ribosylates EF-2, terminating protein synthesis and causing the death of the cell. Diphtheria toxin is highly potent, and as little as one catalytic domain is thought to cause cell death. In cell culture, diphtheria toxin inhibits protein synthesis and causes death in cells carrying the HB-EGF receptor. This toxin has been used to specifically eliminate receptor-expressing cells in transgenic mice.
View List Labs Diphtheria toxins for sale.
View some of List Labs Diphtheria related blogs:
Toxoids, Toxins and Vaccine Related Terminology
List Labs Reagents Used in Research – January ’18
Carrier Protein Used in Life-Changing Research
Cell Ablation Using Diphtheria Toxin (DT) is an Important Technique for Studying Regeneration in Living Animals
By: Mary N. Wessling, Ph.D. ELS
Cross-Reacting Materials: The Motor Behind Conjugate Vaccines
Vaccines in history
The history and practice of vaccination as protection against viral infection is often thought to begin with Edward Jenner’s discovery that cowpox, a viral infection of cows, prevented smallpox in humans. However, it had long been suspected that survivors of smallpox seemed to be immune to further infection. Attempts to induce this immunity, referred to as variolation, had likely been practiced in Africa, Asia, and China, and only introduced to Europe in the 18th century.  Jenner, though, can certainly be credited for his scientific, experimental approach; his inoculation of an 8-year-old boy eventually was documented in his 1798 book An Inquiry into the Causes and Effects of the Variolae vaccinae. A disease discovered in the Western Counties of England . The number of lives that have been saved from misery and death is impossible to grasp; estimates of mortality from the disease before Jenner range between 30 and 35%.
What are carrier proteins, and why are they important in immunology?
Vaccines are often less effective in very young children whose immune systems are immature. For the past 35 years, vaccines have been “conjugated”—combined with a carrier protein –a cross-reactive material (CRM)–that enhances the immunogenicity of polysaccharide antigens.  The carrier protein CRM197 (Product #149), under consideration here, is a mutant version of Diphtheria toxin, in which the single amino acid exchange of a glycine in position 52 to a glutamic acid renders the protein non-toxic: it is one of the most widely used and highly effective carrier proteins . List Labs’ CRM197 has been used in a wide range of medical research, leading to a better understanding of the mechanism behind serious illnesses at all stages of the human life cycle. Most of the studies to date have employed animal models because direct research in humans would be ethically impossible.
Carrier protein CRM 197 could be used to protect premature infants from necrotizing colitis
Starting at the beginnings of life–necrotizing colitis (NEC) destroys the intestinal epithelium and is responsible for 20% to 50% of the mortality in premature infants, as well as causing significant long-term disability among its survivors. In an in vivo experiment using puppies exposed to NEC, Su et al (2013) used List’s CRM 197 as an antagonist to the epithelial protective E-cadherin/b-catenin complex. Their results suggest that administration of the heparin-binding epidermal-like growth factor could protect premature babies from developing NEC, and also that it could be used in treatment of diseases resulting in intestinal injury.
List Labs’ carrier protein used in Alzheimer’s research
A disease that causes misery at the other end of life, Alzheimer’s disease, is associated with amyloid plaques, specifically amyloid-beta, the subject of intense investigation. Vingtdeux et al (2016) in a murine study developed a novel vaccine against the pathologically relevant A-beta pE3 using List’s CRM197 as a carrier protein for epitope presentation.
CRM197 carrier protein impacts humans over a lifetime
In mid-life, three of the research applications of List Labs’ CRM 197 have potential for bringing health to human populations. First, heroin addiction: Jalah et al (2015) sought to develop a vaccine against heroin addiction, one that would block its biological effects by sequestering the drug in the blood, preventing it from crossing the brain barrier. The researchers used List’s CRM197 along with a heroin/morphine hapten conjugate of previously established efficacy to improve its antinociceptive effects.
Another life-shortening threat, diabetic nephropathy is, in 40% of all cases, the leading cause of end-stage kidney disease. You et al (2013) injected CRM 197 in mice for 6 weeks to investigate the mechanism whereby the podocytes (cells in the Bowman’s capsule that filter the blood, foot-shaped, ergo podo…) are injured. The culprit was identified as the proinflammatory M1 subset of macrophages; finding a way to attenuate the effect of the M1 macrophages on the podocytes suggests a new therapeutic approach.
And a final example: Human disease can be caused by contamination of milk products by aflatoxins—certainly a life-long concern. Researchers immunized Holstein Friesian heifers with an experimental vaccine based on the immunogen anaflatoxin B1 AnAFB1] . They then studied the response to AnAFB1 conjugated with List Labs CRM197 carrier proteins to determine the efficacy of inducing antibodies specific to AFB1.
By: Md. Elias, Ph.D, Senior Scientist
List Labs is one of the leading manufacturers of high quality adjuvants from bacterial sources. Our highly purified adjuvants for research and development are Tetanus Toxoid (Product #191), Cholera Toxin B Subunit (Product #104), Diphtheria Toxin CRM197 Mutant (Product #149), Adenylate Cyclase Mutant, Cya-AC– (Product #198L), Pertusis Toxin Mutant (Product #184), and LPS and its derivatives (Products #400, #401, #421, #423, #433, #434). GMP grade material is available by custom order.
In immunology, an adjuvant is a component that enhances and/or potentiates the immune responses (humoral and /or cell mediated) to an antigen and modulates it to achieve the desired immune responses. Adjuvants can be used for various reasons: (i) to enhance the immunogenicity of antigens; (ii) to reduce the amount of antigen or the number of immunizations needed for protective immunity; (iii) to improve the efficacy of vaccines in immune-compromised persons; (iv) to increase functional antibody titer; or (v) as antigen delivery systems for the uptake of antigens by the mucosa (1-3). Brief descriptions of List Labs products that have potential uses as vaccine adjuvants or immune modulators are provided below. For more details, please visit www.ListLabs.com.
Tetanus Toxoid (Product #191): Tetanus toxoid is prepared by formaldehyde inactivation of pure neurotoxin (Product #190). There are FDA approved vaccines that use a tetanus toxoid antigen to protect children and adult against tetanus such as DAPTACEL and Tripedia, and others that use it as a carrier in conjugate vaccines against various pathogens. For example, MenHibrix® is an FDA approved vaccine where tetanus toxoid has been conjugated to Neisseria meningitidis serogroup C and Y capsular polysaccharides and Hib capsular polysaccharide. Several other tetanus toxoid conjugated vaccines are in research and investigation stages such as Type III group B streptococcal polysaccharide-tetanus toxoid conjugate vaccine (4). Information on our entire family of Tetanus products can be found at https://thatsnice-testing6.com/products/tetanus-toxins-&-related-products/.
Cholera Toxin B subunit (Products #103B and #104): Cholera toxin B subunit (CTB) is the cell binding domain of cholera toxin protein complex. The holotoxin consists of a single A subunit bearing ADP-ribosyl-transferase activity surrounded by five B subunits that bind to GM1 ganglioside receptors on mammalian cell surfaces and facilitate entrance of the A subunit into cells. The non-toxic CTB has been shown to be an efficient mucosal adjuvant and carrier molecule for the generation of mucosal antibody responses and/or induction of systemic T-cell tolerance to linked antigens. Due to the ubiquitous presence of the GM1 ganglioside receptor on eukaryotic cell membranes, CTB has been extensively used as a conjugate and non-conjugate vaccine adjuvant in a wide variety of model systems.
A CTB-urease conjugated vaccine has been shown to prevent infection by Helicobacter pylori, a bacterium that infects greater than 50% of world population and can cause a variety of gastrointestinal diseases (5). A series of studies have been carried out to develop CTB carrier based vaccines to prevent HIV-1 (6) and West Nile Virus infections (7). CTB has been used as a component of a skin patch for transcutaneous immunization against hepatitis B virus in a mouse model (8). Besides the adjuvant activity, recent studies show that CTB can suppress immunopathological reactions in allergy and autoimmune diseases such as Crohn’s disease (9). Information on our entire family of Cholera products can be found at https://thatsnice-testing6.com/products/cholera-toxins/.
Diphtheria Toxin CRM197 Mutant (Product #149): CRM197 is a non-toxic mutant of diphtheria toxin lacking the ADP-ribosylation activity (10). CRM197 results from a naturally occuringsingle base change (glutamic acid to glycine) in the toxin gene which is immunologically indistinguishable from the native diphtheria toxin. CRM197 functions as a carrier for polysaccharides and haptens making them immunogenic (11, 12). It is utilized as a carrier to develop conjugate vaccines for diseases such as pneumococcal and meningococcal infections. MenACWY-CRM is an approved vaccine to protect adults and adolescents against disease caused by meningococcal serogroups A, C, W-135 and Y. Information on our entire family of Diphtheria products can be found at https://thatsnice-testing6.com/products/diphtheria-toxins/.
Adenylate Cyclase Toxoid, Cya-AC– (Product #198L): A genetically modified adenylate cyclase toxin (ACT) lacking adenylate cyclase activity (CyaA-AC–) has been produced (13). Although the catalytic activity is destroyed, CyaA-AC– is still cell invasive and able to induce an immune response to co-administered pertussis antigens (14, 15). CyaA-AC– has been shown to promote delivering of vaccine antigens into the cytosol of major histocompatibility complex (MHC) class I antigen-presenting cells (16). CyaA-AC– has been used as a tool to deliver antigens to T-cells in anti-cancer immunotherapeutic vaccines (17, 18).
Pertussis Toxin Mutant (Product #184): List Labs produces Pertussis Toxin Mutant, a genetically inactivated form of pertussis toxin where mutations were introduced to abolish the catalytic activity of the S1 subunit while the toxin complex still retains the cell binding ability (19). A pertusis toxin mutant has been used as an adjuvant or as a carrier to promote an immune response. These studies indicated that pertussis toxin mutant possesses adjuvant properties with the ability to encourage both local and systemic responses, to promote T helper cell responses to co-administered antigens and to favor the production of Th1/Th17 cells, important in mediating host immunity to infectious pathogens (20). Pertusis toxin binds to the cell receptor, TLR4 which activates Rac and subsequently causes various effects depending on the type of cell treated (21). The toxin or binding oligomer induces dendritic cell maturation in a TLR4-dependent manner (22). Information on our entire family of Pertussis products can be found at https://thatsnice-testing6.com/products/pertussis-toxins-&-virulence-factors/.
LPS and its derivatives: List Labs provides LPS and various derivatives: highly purified HPTTM LPS from Escherichia coli O113 (Product #433); Ultar Pure Escherichia coli O111:B4 LPS (Product #421); Escherichia coli O55:B5 LPS (Product #423); Ultra pure LPS from Salmonella Minnesota R595 (Product #434); Lipid A Monophosphoryl from Salmonella Minnesota R595 (Product #401) and highly purified HPTTM LPS from Bordetella pertusis strain 165 (Product #400). For other LPS products please go to our product website. These LPS products are widely used as vaccine adjuvants and immune stimulators.
LPS is a potent stimulator of the vertebrate innate immune system mediated by macrophages and dendritic cells and generates a rapid response to infectious agents. Structural patterns common to diverse LPS molecules are recognized by Toll-like receptors (TLR) and accessory proteins in serum. LPS released from bacterial membranes is bound to LPS binding protein (LBP) in serum, transferred to CD-14, an LPS receptor glycoprotein, and presented to the TLR-4-MD-2 complex, stimulating production of cytokines. LPS has a wide range of uses in research and drug development. It may be used to stimulate immune cells and investigate the innate immune responses. In drug development, structurally modified LPS forms, such as monophophoryl lipid A (MPLA) have been used as adjuvants in a wide range of vaccine formulations. MPLA, a TLR4 agonist has been formulated with liposomes, oil emulsions, or aluminium salts for several vaccines such as malaria vaccine (known as RTS,S) that is comprised of MPLA and a detoxified saponin derivative, QS-21 (3). Information on our entire family of Lipopolysaccharides can be found at https://thatsnice-testing6.com/products/lipopolysaccharides/.
List Labs specializes in producing high quality adjuvants for vaccine development and is interested in partnering with others on new projects. See some of our special projects or contact us for more information.