Anti-Mouse TIGIT [Clone 1B4] — Purified in vivo PLATINUM™ Functional Grade

Clone 1B4 is primarily an antibody used to detect glial fibrillary acidic protein (GFAP) in various species, including mice, with well-established applications in immunohistological analysis and cellular studies of the central nervous system. The most common in vivo applications in mice include:

• Detection and localization of GFAP-expressing astrocytes for studies of CNS development, neuroinflammation, and neurodegenerative disease models.
• Assessment of astrocyte populations and responses in mouse models of brain injury, gliosis, or neurodegenerative disorders.
• Use in multiplex immunohistochemistry alongside other anti-GFAP clones (like 4A11 and 2E1) to enhance sensitivity and specificity in tissue sections.

These applications are fundamental for research into astrocyte biology, glial dysfunction, and disease mechanisms involving the CNS. There are no indications of therapeutic or direct interventional in vivo uses (such as depletion or blocking) for clone 1B4 in mice; its role is mainly analytic or diagnostic within research settings.

Additionally, the antibody’s cross-reactivity allows for comparative studies across species, but its use in mice centers on immunofluorescence, immunohistochemistry, and related techniques to visualize GFAP in tissue sections.

For other proteins (such as CD48, CD18, GPx4, TIGIT) also associated with a clone named 1B4, there is no evidence from search results that these are commonly used for in vivo applications in mice relevant to this context. The dominant and well-documented use of clone 1B4 in vivo in mice pertains to GFAP detection.

Common Antibodies and Proteins Used with 1B4 in the Literature

The "1B4" monoclonal antibody (mAb) is referenced in several different biological contexts, so the answer must be disentangled by application. Here, we focus on research where the 1B4 antibody is central, as in studies of human leukocyte adhesion (anti-CD18 mAb 1B4) and complement receptor type 1 (CR1, anti-CR1 mAb 1B4). In these contexts, commonly paired antibodies and proteins are described below.

Anti-CD18 1B4 (Leukocyte Adhesion)

• Murine 1B4 (m1B4) and Humanized Variants (h1B4): The original 1B4 is a murine monoclonal antibody targeting human CD18 (the β2 integrin subunit). Its humanized versions, such as Gal/Rei, Gal/Len, Jon/Rei, and New/Rei, were created via CDR grafting and functionally compared to m1B4 in blocking assays.
• Dual-Label Immunofluorescence: In bone marrow studies, both m1B4 and the humanized Gal/Rei h1B4 were used in dual-label immunofluorescence microscopy to confirm that the combining site specificity was unaltered by the humanization process.
• Anti-Idiotypic Antibodies: Anti-h1B4 antibodies generated in animal studies were anti-idiotypic (targeting the variable region), while anti-m1B4 antibodies targeted constant and framework regions, highlighting differences in immunogenicity between the murine and humanized forms.
• Functional Assay Targets: The 1B4 antibody's blocking activity was tested against polymorphonuclear leukocytes, monocytes, and their adhesion to human vascular endothelium, as well as in models of leukocyte extravasation in rabbit and monkey skin.

Anti-CR1 1B4 (Complement Receptor 1)

• PfRh4 (Plasmodium falciparum adhesin): In studies of malaria parasite invasion, recombinant PfRh4 was used as a binding partner for complement receptor type 1 (CR1) on erythrocytes. Anti-PfRh4 monoclonal antibody 10C9 was used to detect PfRh4 in ELISA and Western blot, while anti-CR1 mAb 1B4 was used for immunoprecipitation and Western blot detection of CR1.
• HB8592 (anti-CR1 mAb): This antibody, which recognizes soluble CR1 (sCR1) but not specific CR1 domains (CCP1-3 or CCP15-17), was used in competitive ELISA to detect CR1 binding to PfRh4.
• Recombinant CR1 Constructs (CCP1-3, CCP15-17): These were used in competitive binding assays alongside anti-CR1 antibodies to map the interaction site between CR1 and PfRh4.
• Protein G/A Sepharose Beads: Used for immunoprecipitation of CR1–PfRh4 complexes with anti-CR1 mAb 1B4.

Summary Table

Other Uses of "1B4" (Clarification)

The name "1B4" is also used for monoclonal antibodies targeting other proteins, such as FGF5, RBM8A, CTR1, GTF2IRD2, and GFAP, but these are distinct from the anti-CD18 and anti-CR1 1B4 discussed above, and their commonly used partners are not described in the provided literature.

Key Points

• In leukocyte adhesion research, 1B4 is primarily paired with its own murine and humanized variants for functional and specificity studies.
• In malaria and CR1 biology, 1B4 is used alongside PfRh4, anti-PfRh4 antibody 10C9, anti-CR1 antibody HB8592, and recombinant CR1 domain constructs for interaction mapping and detection.
• No cross-reactivity or routine pairing with antibodies targeting unrelated molecules (e.g., BLTR, intermediate filaments) is indicated in the provided literature for the anti-CD18 or anti-CR1 1B4 contexts.

In summary: The most commonly used antibodies and proteins with 1B4 in the literature depend on the biological context—leukocyte adhesion or CR1/PfRh4 interaction—and include species-specific variants of 1B4 itself, anti-PfRh4 10C9, HB8592, and recombinant CR1 domain constructs.

Overview

The designation "clone 1B4" appears in several distinct scientific contexts, each referring to a different biological reagent (cell line, monoclonal antibody, or plant clone). Below, the key findings for each context are summarized separately for clarity.

Human Pancreatic Beta Cell Line: 1.1B4

• Origins and Characteristics: The 1.1B4 cell line is a human beta cell line generated by fusing primary human pancreatic beta cells with the PANC-1 pancreatic ductal carcinoma cell line. This hybrid was developed to model human beta cell responses in culture, particularly for studying persistent enteroviral infections relevant to type 1 diabetes.
• Insulin Expression: Immunocytochemical studies revealed that cloned h1.1B4 cells (human-enriched subclones) do not express immunoreactive insulin, unlike other beta cell models such as EndoC-βH1 cells.
• Stimulus-Secretion Coupling: Despite lacking insulin production, h1.1B4 cells retain a functional stimulus-secretion coupling pathway. When transfected with a human growth hormone (hGH) construct, these cells can secrete hGH in response to appropriate stimuli, indicating preserved secretory machinery.
• Interferon Response: The h1.1B4 subclones show robust responses to human interferon-α (IFNα), upregulating interferon-response proteins like MDA5, ISG15, PKR, and STAT1. They also respond to transfection with polyI:C, a viral mimic.
• Utility: The 1.1B4 line is particularly useful for studying persistent viral infections in human beta cells and interferon signaling, but not for insulin biosynthesis studies.

Monoclonal Antibody: Anti-TIGIT Clone 1B4

• Function: Clone 1B4 is a monoclonal antibody targeting TIGIT, an immune checkpoint receptor. Unlike other anti-TIGIT clones (4D4, 1G9) that act as agonists and suppress T cell responses, clone 1B4 functions as a blocking antibody.
• In Vitro vs. In Vivo Effects: In vitro, clone 1B4 does not affect T cell proliferation, but in vivo, it enhances antigen-specific T cell proliferation and increases secretion of pro-inflammatory cytokines (IFN-γ, IL-17) upon antigen rechallenge.
• Disease Modulation: In a mouse model of experimental autoimmune encephalomyelitis (EAE), treatment with clone 1B4 exacerbates disease severity, increasing the number of CNS lesions and frequencies of Th17 cells. This is consistent with its role as a TIGIT-blocking antibody, similar to the phenotype seen in TIGIT-deficient mice.
• Non-Depleting: Clone 1B4 is confirmed to be non-depleting in vivo, meaning it blocks TIGIT signaling without causing antibody-dependent cell depletion.

Other Contexts

• Mouse Anti-Human MYD88 (Clone 1B4): This is a monoclonal antibody raised against full-length human MYD88, used as a research tool, but no functional or disease-related findings are highlighted in the available citation.
• Plant Clone 717-1B4: This Populus clone was used to study ethylene biosynthesis; over-expression of ACS8 in 717-1B4 leads to elevated ethylene and stem dwarfism, but this is unrelated to the immunological or beta cell contexts above.

Summary Table: Key Findings by Context

Conclusion

Clone 1B4 has distinct roles in different fields. In diabetes research, it refers to a human beta cell line useful for studying viral infections and interferon responses but not insulin production. In immunology, it designates a blocking anti-TIGIT monoclonal antibody that enhances T cell responses and exacerbates autoimmune disease in vivo. Always consider the specific biological context when interpreting findings related to "clone 1B4."

The dosing regimens of clone 1B4, which is an anti-TIGIT antibody, can vary across different mouse models depending on the specific experimental context and the desired outcome.

1. Dose: The dose of clone 1B4 typically used in mouse models ranges from 100 μg to 200 μg per dose. For example, in experiments involving the blockade of TIGIT, a dose of 100 μg per dose is often used.

2. Administration Schedule: The administration schedule can vary. In some studies, 1B4 is administered on specific days, such as days 1, 3, and 5 after randomization, to evaluate its effects on immune responses.

3. Model-Specific Effects: Clone 1B4 acts as a blocking antibody, which means it can enhance immune responses by inhibiting the TIGIT pathway. This can result in increased disease severity in autoimmune models like experimental autoimmune encephalomyelitis (EAE). In cancer models, such as the MC38 colon carcinoma, 1B4 can retard tumor growth.

4. Route of Administration: While specific routes are not detailed in all studies, antibodies are commonly administered via intraperitoneal injection in mouse models.

Given these variations, the dosing regimen for clone 1B4 should be tailored to the specific research question and experimental design.