Anti-Human HLA-DQ (MHC Class II) [Clone 1a3] — Purified in vivo PLATINUM™ Functional Grade

The most common in vivo applications of clone 1a3 in mice involve its use as part of a transcription factor cocktail (Hnf1α and Foxa3) to directly reprogram mouse fibroblasts into induced hepatic stem cells (iHepSCs) and further into induced cholangiocyte progenitor cells (iCPCs) for liver regeneration or disease modeling.

Supporting details:

• Clone 1a3 targets human HLA-DQ (MHC Class II) and is exploited to study cellular reprogramming, particularly for generating hepatic progenitor populations from mouse fibroblasts.
• These reprogrammed cells are then often transplanted into mouse liver injury models in vivo to assess their potential for liver tissue regeneration, disease modeling, or therapeutic intervention.
• While clone 1a3 is frequently described for its immunological specificity (anti-human HLA-DQ), its documented in vivo use in mice is primarily within liver stem/progenitor cell reprogramming and transplantation protocols, rather than traditional immune cell depletion or xenograft rejection.

Additional insights:

• There is no strong evidence in the provided results for routine use of clone 1a3 in classical immune cell depletion, tumor xenograft rejection, or immune modulation studies in mice, unlike other monoclonals used for such immunological in vivo applications.
• The antibody does not cross-react with HLA-DR or HLA-DP, ensuring specificity for HLA-DQ antigens when humanized immune system models or tissues are involved.

In summary, in vivo applications of clone 1a3 in mice are centered on direct cellular reprogramming to hepatic progenitors for liver research and regenerative studies.

Commonly Used Antibodies and Proteins with 1a3

The clone 1a3 is most frequently associated with anti-human HLA-DQ antibodies. These are widely utilized in immunological research, particularly for detecting HLA-DQ, a class II major histocompatibility complex (MHC) molecule expressed on certain immune cells. The 1a3 antibody is known to recognize a monomorphic epitope present on virtually all HLA-DQ molecules, but not on HLA-DR or HLA-DP.

Context in the Literature

Although the search results do not provide extensive lists of specific companion antibodies or proteins routinely used alongside 1a3 in co-staining or functional experiments, some general patterns and relevant categories can be inferred from available information.

General Classes of Commonly Used Antibodies/Proteins:

• Signaling Pathway Markers: According to Leinco, 1a3 can be used with signaling pathway markers (e.g., anti-ERK, anti-MEK) as PLA (Proximity Ligation Assay) partner antibodies for visualizing protein interactions. This suggests that 1a3 may be paired with antibodies targeting intracellular signaling molecules in studies of immune cell activation or signaling complexes.
• MHC Class II-Related Proteins: Given that 1a3 targets HLA-DQ, it is logical that related MHC class II molecules (e.g., HLA-DR, HLA-DP) and their associated proteins (such as invariant chain, HLA-DM, and HLA-DO) could be used in parallel, although the 1a3 clone itself does not cross-react with HLA-DR or HLA-DP.
• Peptides for Binding Studies: Research on HLA-DQ often involves synthetic peptides or recombinant proteins for binding studies, particularly to investigate the role of peptide loading in antibody reactivity (e.g., peptides from HLA class I bound to HLA-DQ molecules). While these are not antibodies, they are essential tools in functional studies involving 1a3.
• Alternative Binding Reagents: The literature notes the use of alternative reagents such as monobodies, DARPins, affibodies, and anticalins in protein interaction studies. While not antibodies, these engineered proteins can serve similar roles in research applications.

Examples from Specific Studies

• Polymorphic HLA Class I Peptides: A study highlights that antibodies reactive to HLA-DQβ0603:DQα0103 recognize not only the HLA-DQ molecule itself but also peptides derived from HLA class I heavy chains bound to HLA-DQ, suggesting that peptide-MHC complexes are relevant targets when using 1a3 in serological or functional assays.
• PLA Partner Antibodies: In proximity ligation assays, 1a3 may be paired with antibodies against signaling molecules (e.g., ERK, MEK) to study protein-protein interactions in immune cells.

Summary Table

Key Points

• 1a3 (anti-HLA-DQ) is most commonly paired with signaling pathway antibodies (e.g., anti-ERK, anti-MEK) in PLA and potentially in co-staining experiments.
• Peptides, especially those derived from HLA class I and bound to HLA-DQ, are critical in functional assays involving 1a3.
• Engineered binding proteins (monobodies, DARPins, etc.) are sometimes used as alternatives to traditional antibodies in interaction studies.
• No direct cross-reactivity with HLA-DR or HLA-DP is reported for the 1a3 clone.

In summary, while there is limited explicit documentation of exact companion antibodies or proteins used with 1a3, the most common co-targets in the literature are intracellular signaling markers (for PLA), MHC class II-related molecules (for comparative studies), and synthetic peptides (for functional and binding assays). Alternative protein binders are also used in some specialized applications.

The search results do not provide comprehensive information about key findings specifically associated with "clone 1a3" in the scientific literature. However, based on the available information:

1. Anti-Human HLADQ (MHC Class II) Antibody: The "clone 1a3" is mentioned in the context of an antibody used for staining cells in flow cytometry, specifically for the HLA-DQ antigen. The suggested concentration for staining is ≤ 1.0 μg per 10^6 cells in a volume of 100 μl.

2. Heterologous Expression: While not directly related to "clone 1a3," there is a mention of heterologous expression of the UGT1A3 enzyme in Chinese hamster lung (CHL) cells, which might be of interest if looking for related concepts.

3. Miscellaneous Mention: In other contexts, "Clone 1A3" is mentioned in research related to different genetic or biochemical analyses, but these do not specifically relate to "clone 1a3" in a way that would provide key findings relevant to the query.

In summary, there is limited direct information about "clone 1a3" in the provided search results. The most relevant information pertains to the use of an antibody clone in immunological studies.

Dosing regimens for clone 1a3 (anti-human HLA-DQ, MHC Class II) in mouse models are determined by several variables, notably target engagement, mouse strain/humanization, and experimental objectives. According to available sources, there are no published in vivo mouse dosing regimens specifically described for clone 1a3 to date.

Key factors influencing dosing regimens include:

• Target engagement: The dosing amount must achieve sufficient antibody levels to effectively bind the human HLA-DQ target, which varies based on the expression level and location of HLA-DQ in the model.
• Mouse strain/humanization: Dosing adjustments may be necessary depending on whether the model is fully murine, partially humanized, or transgenic for HLA molecules, as differences in pharmacokinetics or immune response can affect efficacy. For example, in humanized models like B-HLA-A3.1 mice, antigen expression levels and tissue distributions differ from wild-type strains.
• Experimental objective: Regimens can shift depending on whether the aim is target depletion, tolerance induction, or other endpoints, which dictate the intensity and frequency of dosing.

No direct mouse model dosing examples for clone 1a3 are found in the current literature. Standard antibody dosing regimens for other similar in vivo murine studies (e.g., anti-CD3, anti-PD-1) often use doses ranging from 5–500 µg per mouse, with schedules from single to repeated (every 3–4 days), typically administered intraperitoneally or intravenously. However, these regimens are antibody- and target-specific and cannot be directly substituted for clone 1a3 without empirical validation.

In summary:

• No published in vivo mouse dosing regimens are currently available for clone 1a3.
• Dosing must be empirically determined for each model, guided by target engagement, mouse strain, and specific scientific goals.
• Reference dosing regimens for similar antibodies range widely (5–500 μg/mouse), but cannot be assumed for clone 1a3 without specific validation.

If a precise dosing protocol for clone 1a3 in mice is needed, experimental pilot studies are recommended, starting with doses and schedules typical for monoclonal antibodies and adjusting based on pharmacodynamic and pharmacokinetic results.