#tetramers

[whats-in-a-sentence]

The MADS box genes share a characteristic, conserved nucleotide sequence known as a MADS box, which encodes a protein structure known as the MADS domain (Figure 20.28A). (...) When the tetramers bind two different CArG-boxes on the same target gene, the boxes are brought into close proximity, causing DNA bending (Figure 20.28B). (...) These tetramers are hypothesized to bind CArG-boxes on target genes and modify their expression (see Figure 20.28 B).

"Plant Physiology and Development" int'l 6e - Taiz, L., Zeiger, E., Møller, I.M., Murphy, A.

[tenth-sentence]

According to the model, tetramers composed of different homodimers and heterodimers of MADS domain proteins can exert combinatorial control over floral organ identity.

"Plant Physiology and Development" int'l 6e - Taiz, L., Zeiger, E., Møller, I.M., Murphy, A.

[i-am-q]

Those that were allowed to use the ATP battery in my brain for their “double blind” study up until Jan. 2024, I respect you but respectfully ask for full control of my body again—whatever that means.

Those with access to the slave cameras through the company, keep it up (A plus as they say). The world is behind you.

[covid-safer-hotties]

SARS-CoV-2-specific CD8+ T cells from people with long COVID establish and maintain effector phenotype and key TCR signatures over 2 years - Published Sept 16, 2024

Significance Long COVID occurs in small but important minority of patients following COVID-19, reducing quality of life and contributing to healthcare burden. Although research into underlying mechanisms is evolving, immunity is understudied. As the recall of T cell memory promotes more rapid recovery and ameliorates disease outcomes, establishment of robust memory T cells is important for protection against subsequent infections, even when the virus mutates. We defined how SARS-CoV-2-specific T cell and B cell responses are established and maintained following infection and vaccination for 2 y in people with long COVID. We found robust and prototypical SARS-CoV-2-specific T cells with effector phenotype and key T cell receptor signatures in people with long COVID following SARS-CoV-2 infection and subsequent COVID-19 vaccination.

Abstract Long COVID occurs in a small but important minority of patients following COVID-19, reducing quality of life and contributing to healthcare burden. Although research into underlying mechanisms is evolving, immunity is understudied. SARS-CoV-2-specific T cell responses are of key importance for viral clearance and COVID-19 recovery. However, in long COVID, the establishment and persistence of SARS-CoV-2-specific T cells are far from clear, especially beyond 12 mo postinfection and postvaccination. We defined ex vivo antigen-specific B cell and T cell responses and their T cell receptors (TCR) repertoires across 2 y postinfection in people with long COVID. Using 13 SARS-CoV-2 peptide–HLA tetramers, spanning 11 HLA allotypes, as well as spike and nucleocapsid probes, we tracked SARS-CoV-2-specific CD8+ and CD4+ T cells and B-cells in individuals from their first SARS-CoV-2 infection through primary vaccination over 24 mo. The frequencies of ORF1a- and nucleocapsid-specific T cells and B cells remained stable over 24 mo. Spike-specific CD8+ and CD4+ T cells and B cells were boosted by SARS-CoV-2 vaccination, indicating immunization, in fully recovered and people with long COVID, altered the immunodominance hierarchy of SARS-CoV-2 T cell epitopes. Meanwhile, influenza-specific CD8+ T cells were stable across 24 mo, suggesting no bystander-activation. Compared to total T cell populations, SARS-CoV-2-specific T cells were enriched for central memory phenotype, although the proportion of central memory T cells decreased following acute illness. Importantly, TCR repertoire composition was maintained throughout long COVID, including postvaccination, to 2 y postinfection. Overall, we defined ex vivo SARS-CoV-2-specific B cells and T cells to understand primary and recall responses, providing key insights into antigen-specific responses in people with long COVID.

[sci-memes-yura15cbx]

Оригинальный анекдот:

Точечная мутация в 6 кодоне гена β-цепи глобина приводит к замещению глютаминовой кислоты на валин. Включение βs-цепи в тетрамер приводит к образованию Hbs. Нерастворимость деоксигенированного Hbs приводит к его полимеризации и, как следствие, к снижению деформабельности и образованию серповидных эритроцитов - Серповидноклеточной анемии.

Алё, это Генадий Петрович?

Нет, это Мухрат Ибрагимович

А это номер 25-36-77 ?

Нет, 25-36-78.

Надо же, ошибка 6-м знаке и такой эффект!

***

Original joke:

A point mutation in codon 6 of the globin β-chain gene results in the substitution of glutamic acid for valine. The incorporation of the βs chain into the tetramer leads to the formation of Hbs. The insolubility of deoxygenated Hbs leads to its polymerization and, consequently, to a decrease in deformability and the formation of sickle-shaped erythrocytes - sickle cell anemia.

Hello, is this Moishe?

No, this is Muhammad.

Is this number 25-36-77?

No, 25-36-78.

Wow, an error on the 6th sign and such an effect!

***

chiste original:

Una mutación puntual en el codón 6 del gen de la cadena β de la globina da como resultado la sustitución del ácido glutámico por valina. La incorporación de la cadena βs en el tetrámero conduce a la formación de Hbs. La insolubilidad de la Hbs desoxigenada conduce a su polimerización y, en consecuencia, a una disminución de la deformabilidad y la formación de eritrocitos en forma de hoz: anemia de células falciformes.

Hola, ¿es Moishe?

No, este es Mahoma.

¿Este es el número 25-36-77?

No, 25-36-78.

¡Vaya, un error en el sexto signo y tal efecto!

Ошибка 6-м знаке и такой эффект!

Error 6th sign and such an effect!

¡Error en el sexto signo

Мои мемы my memes

[ayanroot1]

Propylene Tetramer Market 🛢️

The propylene tetramer market is witnessing steady growth due to its increasing use in various industrial applications such as the production of chemicals, polymers, and fuel additives. Propylene tetramer offers versatile properties that make it essential in several end-use industries.

Market Trends:

Rising demand for propylene tetramer in the production of high-performance plastics and lubricants.

Growing use in the manufacturing of alkylates, which are essential for gasoline blending.

Expansion of the chemical and automotive industries driving the need for propylene tetramer.

Innovations in refining technology for efficient production of propylene tetramer.

Key Players:

ExxonMobil

SABIC

Reliance Industries

LyondellBasell

Chevron Phillips Chemical Company

The market is driven by advancements in refining processes, growing demand for fuel additives, and the increasing need for specialty chemicals.

👉 Learn more: https://www.globalmarketstatistics.com/market-reports/propylene-tetramer-market-11481

[moleculardepot]

Native Rabbit Pyruvate Kinase

Native Rabbit Pyruvate Kinase Catalog number: B2017310 Lot number: Batch Dependent Expiration Date: Batch dependent Amount: 25 kU Molecular Weight or Concentration: 237 kDa, tetramer of four identical subunits 57 kDa Supplied as: Powder Applications: a molecular tool for various biochemical applications Storage: −20°C Keywords: Pyruvate kinase PKM, Pyruvate kinase muscle isozyme, ATP: Pyruvate…

[mblinternationalcorporation]

Non-Classical MHC Tetramers in Health and Disease: Emerging Trends

Major Histocompatibility Complex (MHC) molecules are essential components of the immune system, playing a crucial role in antigen presentation and immune response. Traditionally, research has focused on classical MHC molecules (MHC class I and II). However, recent advances have highlighted the significance of non-classical MHC molecules, specifically non-classical MHC tetramers, in health and disease. These molecules have distinct structural and functional properties that differentiate them from their classical counterparts, offering new insights and therapeutic possibilities in immunology.

Understanding Non-Classical MHC Molecules

Non-classical MHC molecules, including HLA-E, HLA-F, HLA-G in humans, and their murine equivalents (Qa-1, Qa-2, and others), exhibit limited polymorphism compared to classical MHC molecules. They are expressed in specific tissues and have unique roles in immune regulation, such as tolerance induction and modulation of immune responses. Non-classical MHC molecules present a broader range of antigens, including non-peptidic antigens, lipids, and small molecules, to specialized subsets of T cells and natural killer (NK) cells.

Structure and Function of Non-Classical MHC Tetramers

Non-classical MHC tetramers are complexed structures composed of four MHC molecules bound to specific antigens, forming a tetramer that can be used to stain antigen-specific T cells. These tetramers are valuable tools for studying the immune response, allowing researchers to track and characterize antigen-specific T cells with high precision. Unlike classical MHC tetramers, non-classical MHC tetramers often interact with non-peptidic antigens and can engage with both T cell receptors (TCRs) and NK cell receptors, broadening their functional scope.

Antigen Presentation

One of the primary functions of non-classical MHC tetramers is to present antigens to T cells and NK cells. For instance, HLA-E tetramers present peptides derived from the leader sequences of other MHC class I molecules, interacting with the CD94/NKG2 receptor on NK cells and some T cells. This interaction plays a crucial role in immune surveillance and the regulation of NK cell activity, contributing to the recognition of infected or transformed cells.

Immune Regulation

Non-classical MHC tetramers also contribute to immune regulation. HLA-G tetramers, for example, are involved in immune tolerance, particularly during pregnancy. HLA-G expression on trophoblasts helps to protect the fetus from maternal immune attack by interacting with inhibitory receptors on NK cells and T cells. This immune modulatory function is critical for maintaining a healthy pregnancy and preventing autoimmune responses.

Non-Classical MHC Tetramers in Health

Infection

Non-classical MHC tetramers play vital roles in the immune response to infections. For instance, HLA-E tetramers can present viral peptides to NK cells, enhancing their ability to recognize and eliminate infected cells. This mechanism is particularly important in viral infections where pathogens downregulate classical MHC molecules to evade immune detection. By presenting conserved viral peptides, non-classical MHC molecules ensure the immune system can still identify and respond to infected cells.

Cancer

In the context of cancer, non-classical MHC tetramers offer promising therapeutic avenues. Tumors often exploit immune checkpoints and inhibitory pathways to evade immune surveillance. HLA-G tetramers, which interact with inhibitory receptors on immune cells, are frequently upregulated in various cancers. Understanding this interaction has led to the development of strategies to block HLA-G mediated immune suppression, enhancing the anti-tumor immune response. Additionally, non-classical MHC tetramers can be used to identify tumor-specific T cells, facilitating the development of targeted immunotherapies.

Autoimmunity and Tolerance

Non-classical MHC tetramers are also implicated in autoimmune diseases and immune tolerance. For example, the expression of HLA-G and its interaction with immune inhibitory receptors is associated with the regulation of autoimmune responses. By promoting tolerance, non-classical MHC molecules help to prevent excessive immune activation that can lead to tissue damage in autoimmune diseases such as multiple sclerosis and rheumatoid arthritis.

Non-Classical MHC Tetramers in Disease

Viral Infections

In viral infections, pathogens often evolve mechanisms to evade classical MHC-mediated immune responses. Non-classical MHC molecules provide an alternative pathway for immune recognition. For instance, HCMV (human cytomegalovirus) downregulates classical MHC class I molecules to avoid detection by cytotoxic T lymphocytes (CTLs). However, HLA-E tetramers can present viral peptides to NK cells, compensating for the loss of classical MHC presentation and maintaining immune pressure on the virus.

Cancer Immune Evasion

Cancer cells frequently upregulate non-classical MHC molecules to escape immune detection. HLA-G expression, for example, is associated with poor prognosis in various cancers, including ovarian, breast, and colorectal cancers. By interacting with inhibitory receptors on immune cells, HLA-G tetramers suppress anti-tumor immune responses, facilitating tumor growth and metastasis. Understanding these interactions has prompted the development of therapeutic strategies aimed at blocking HLA-G and restoring effective immune surveillance.

Autoimmune Diseases

Autoimmune diseases result from an imbalance in immune regulation, where the immune system mistakenly targets self-tissues. Non-classical MHC molecules like HLA-G play a protective role by promoting immune tolerance. In diseases such as systemic lupus erythematosus (SLE) and rheumatoid arthritis, altered expression of HLA-G has been observed. Therapeutic modulation of HLA-G expression and function holds potential for restoring immune balance and mitigating autoimmune pathology.

Emerging Trends and Future Directions

Novel Tetramer Technologies

Recent advancements in tetramer technology have expanded the capabilities of non-classical MHC tetramers. Innovations include the development of multi-antigen tetramers, which can present multiple antigens simultaneously, enhancing the detection of diverse T cell populations. Additionally, improvements in tetramer stability and affinity have increased their utility in clinical and research settings.

Immunotherapy Applications

The unique properties of non-classical MHC tetramers make them attractive candidates for immunotherapy. By targeting specific immune pathways and cell populations, non-classical MHC tetramers can be used to design personalized immunotherapies for cancer and autoimmune diseases. For example, blocking HLA-G interactions or enhancing HLA-E-mediated immune responses are promising strategies for boosting anti-tumor immunity and regulating autoimmune reactions.

Biomarker Discovery

Non-classical MHC tetramers hold potential as biomarkers for disease diagnosis and prognosis. Elevated levels of HLA-G, for instance, are associated with poor outcomes in cancer patients. Monitoring non-classical MHC tetramer expression and function can provide valuable insights into disease progression and treatment efficacy. As research advances, the identification of novel biomarkers will enhance our ability to diagnose and treat various immune-related conditions.

Conclusion

Non-classical MHC tetramers represent a fascinating and rapidly evolving field in immunology. Their unique structural and functional characteristics distinguish them from classical MHC molecules, offering new insights into immune regulation and disease mechanisms. From infection and cancer to autoimmunity and tolerance, non-classical MHC tetramers play pivotal roles in health and disease. Emerging trends in tetramer technology, immunotherapy, and biomarker discovery promise to unlock new therapeutic possibilities and improve our understanding of the immune system. As research continues to unfold, non-classical MHC tetramers will undoubtedly remain at the forefront of immunological innovation.

[12nb34]

📆 Jan 2023 📰 Exposed seronegative: Cellular immune responses to SARS-CoV-2 in the absence of seroconversion 🗞 Frontiers

Determining which antigens are targeted in SARS-CoV-2 ESNs provides insight into mechanisms of response. T-cells targeting the replication-transcription complex (RTC) of SARS-CoV-2 were described by Swadling et al. (2022) in ESNs (7). The RTC is comprised of the RNA polymerase NSP12, a co-factor NSP7, and the helicase NSP13 (37). Its expression early in the SARS-CoV-2 replication cycle makes the RTC a target for rapidly-induced T-cell responses (7). The authors identified fivefold-higher RTC-specific T-cell responses in ESNs compared to unexposed controls. Furthermore, cellular immunity in ESNs preferentially targeted the RTC over structural proteins compared to seropositive individuals. However, the authors did not assay cellular responses to other NSPs.

In a study of six ESN sexual partners of HSV-2-infected individuals by Posavad et al. (2010), T cell responses in ESNs were skewed towards peptides expressed early in the virus replication cycle, whereas HSV-2 seropositive individuals more frequently generated responses to structural proteins present in virions. The authors speculated that this skew in ESNs reflected early T-cell engagement with infected cells before the production of infectious virions. Together, these data support a model whereby rapid T-cell responses targeting early translated NSPs may prevent infection from gaining a foothold.

To prevent infection before seroconversion, a rapid cellular response appears critical. Chandran et al. (2021) assayed weekly nasopharyngeal swabs and blood samples from HCWs, and demonstrated that SARS-CoV-2 specific T-cell proliferation can occur before PCR positivity (42). These rapid responses may originate from pre-existing, cross-reactive T-cells specific for human coronaviruses (HCoVs). Cross-recognition of SARS-CoV-2 by HCoV-specific T-cells has been widely described (43–50), and T-cells from COVID-19 convalescents preferentially target conserved epitopes over SARS-CoV-2-specific epitopes (49). HCWs display higher levels of HCoV-specific T-cells than community controls (28), which may contribute to the abundance of ESNs amongst HCWs. The activation of cross-reactive T-cells by related viruses has been termed ‘heterologous immunity’ (51). This is distinct from autologous viral infection in that neutralising antibody responses to the heterologous virus may be suboptimal, allowing cellular memory to dominate.

The RTC is highly conserved between SARS-CoV-2 and HCoVs (7). Tetramer staining of T-cells with an HCoV-HKU1 homologue of the RTC component NSP7 showed strong responses in SARS-CoV-2 ESNs. Swadling et al. (2022) suggested that prior exposure to HCoV-HKU1 generates cross-reactive T-cells specific for NSP7, enabling rapid abortion of SARS-CoV-2 infection (7). A study of camel workers in Saudi Arabia identified both CD4+ and CD8+ responses to Middle-East Respiratory Syndrome coronavirus in four highly-exposed seronegative individuals, suggesting that the ESN phenomenon may be common to other human-infective coronaviruses.

Cellular immunity is able to clear SARS-CoV-2 infection in isolation; patients with X-linked agammaglobulinemia who cannot produce antibodies eventually clear SARS-CoV-2 infection, and mount higher magnitude CD8+ T-cell responses to SARS-CoV-2 compared to immunocompetent individuals (54). However, in Wang et al. (2021) the magnitude of the SARS-CoV-2-specific CD4+ T-cell response was twice as high in infected individuals compared to ESNs. This casts doubt on their role in protection against infection.

[selkypostergirl]

I promise it looks like hexavalent carbon on first blush but it really isn’t! It’s a weird tetramer with a delocalized electron system

Check out the 3D model, it’s a really good way to see the weird way the bonding works

Organometallic chemistry is a beautiful lawless land

Fundamentally there’s 2 kinds of scary chemistry:

The kind that scares laypeople

And the kind that scares chemists

[mechecolomar-archive]

I need 80 treasures for harry flynn's outfit :(

[biolegend]

What are tetramers? What is Flex-T™? How are they made? Why are they useful? Find out in this blog (http://www.biolegend.com/newsdetail/4307/)! BioLegend develops and manufactures world-class, cutting-edge immunological reagents for biomedical research, offered at an outstanding value.