In direct support of the fight against the novel coronavirus and the world's effort to understand more about the mechanisms of the COVID-19 disease, we're proud to announce the arrival of our SARS-CoV-2 Neutralizing Antibody.

Over these past few months, we here at ABclonal have been working diligently to continue supplying necessary reagents to researchers, clinicians, and companies worldwide to facilitate their efforts during the COVID-19 pandemic. In direct support of that goal, we’re proud to introduce our new, comprehensive line of SARS-CoV-2 ELISA kits.

A healthy immune system requires a series of checkpoints to ensure self tolerance and prevent damage to other tissues during immune response. Binding of costimulatory signal transduction molecules (such as CD28, ICOS, GITR) on T cells to their receptors (such as CD80/CD86, ICOSL, GITRL) on antigen presenting cells (APCs) may contribute to T cell activation. However, in some states, inhibitory signals of T cell activation and response occur during the involvement of T cell receptors. These signals are generated by proteins involved in immune checkpoints (eg, PD-1, CTLA-4, TIM-3, and LAG3). Usually PD-1 and CTLA-4 immunological checkpoint proteins are upregulated in T cells infiltrating tumors and bind to their respective ligands, PD-L1 (ligand B7-H1)/PD-L2 (ligand B7- DC) and CD80/86, and down-regulate T cell responses. Immunological checkpoint ligands are often upregulated in cancer cells as a means of evading immune detection. Therefore, immunotherapy by blocking immunological checkpoint protein activation of anti-tumor immunity has become a popular research subject for cancer therapy.

The G2/M cycle checkpoint prevents cells with genomic DNA damage from entering mitosis (M phase). The main safeguards conferred by this checkpoint is to ensure that DNA is free of major lesions or replication errors, and there are enough organelles, metabolites, and other cellular cargo in the parent cell prior to division so the daughter cells can be adequately provided for once mitosis is complete. Failures at this checkpoint are associated with aberrant cellular growth and cancer progression.

The Cyclin B-CDK1 complex plays an important regulatory role during the G2 transition, at which time CDK1 is maintained inactivated by the tyrosine kinases Wee1 and Myt1. When the cells enter the M phase, the kinase Aurora A and the cofactor Bora act together to activate PLK1, which in turn activates the activity of phosphatase CDC25 and downstream CDC2, effectively driving the cells into mitosis. When the DNA is damaged, it activates the DNA-PK/ATM/ATR kinase and eventually inactivates the Cyclin B-CDK1 complex. Stopping cell cycle progression allows the cell enough time to attempt to repair any DNA or cellular damage, and if all else fails, to induce apoptosis to prevent risk to the entire organism.

ABclonal Technology provides a wide selection of cell cycle checkpoint antibody products for every phase of a cell's life. Please see a small sample of our offerings below.

The G1/S cell cycle checkpoints control whether eukaryotic cells enter the S phase (synthesis phase) of DNA synthesis after having properly completed the G1 phase to ensure the cell has enough energy and resources to begin DNA replication. Two cell cycle kinase complexes, CDK4/6-Cyclin D and CDK2- Cyclin E, work together to relieve the inhibition of dynamic transcriptional complexes containing retinoblastoma protein (Rb) and E2F. In cells undefined during the G1 phase, hypophosphorylated Rb binds to the E2F-DP1 transcription factor and forms an inhibitory complex with HDAC, thereby inhibiting downstream key transcriptional activities. Clear entry into the S phase is achieved by continuous phosphorylation of Rb by Cyclin D-CDK4/6 and Cyclin E-CDK2, which separates the transcription factor E2F from the inhibitory complex and allows transcription of the gene required for DNA replication. After the growth factor disappears, the expression level of cyclin D is down-regulated by down-regulation of protein expression and phosphorylation-dependent degradation. Without a proper G1/S checkpoint, the cell could arrest or potentially undergo aberrant processes that could lead to disease states such as cancer.

Embryonic stem cells (ES cells) are pluripotent stem cells isolated from an inner cell mass of early-stage embryo-blastocysts. ES cells have a high differentiation potential., which means that they have the capacity to develop into whatever cell type the body needs depending on the signals received by the ES cell. At the same time, while ES cells are undifferentiated, they retain the potential to infinitely replicate, making them highly attractive and renewable subjects for targeted cell therapy and regenerative medicine.