OASA1 Antibody

What is OAS1 and what are its primary biological functions?

OAS1 (2'-5'-oligoadenylate synthase 1), also known as E18/E16 and p46/p42 OAS, belongs to the OAS family of genes induced by interferons (IFN) and viruses. It plays a crucial role in regulating signaling pathways during viral infection . OAS1's antiviral function is primarily attributed to its ability to detect short double-stranded RNAs (dsRNAs) .

OAS1 shares structural and functional homology with cyclic GMP-AMP (cGAMP) synthetase (cGAS), and both proteins initiate antiviral immune responses by recognizing cytoplasmic foreign nucleic acids — OAS1 detects viral double-stranded RNA (dsRNA) while cGAS recognizes viral double-stranded DNA (dsDNA) . Upon activation, OAS1 produces 2'-5'-oligoadenylate (2-5A) second messengers that activate RNase L, which subsequently degrades viral and cellular RNA to interfere with viral propagation .

Beyond viral infections, OAS1 has been implicated in autoimmune diseases and cancer processes. Research indicates it can affect cell migration, and high OAS1 mRNA expression has been linked to worse prognosis in breast cancer patients .

What are the key considerations when selecting an OAS1 antibody for research?

When selecting an OAS1 antibody for research applications, consider:

• Antibody specificity: Verify the antibody recognizes your target OAS1 isoform (p46/p42) and doesn't cross-react with other OAS family members. Anti-OAS1 antibodies should be validated against specific OAS1 protein variants .

• Host species and format: For OAS1, goat-derived polyclonal antibodies are commonly available, often as purified IgG in liquid form . Consider experimental compatibility with your secondary detection system.

• Validated applications: Confirm the antibody has been validated for your specific application (Western blot, immunohistochemistry, etc.).

• Target species reactivity: Ensure the antibody recognizes OAS1 from your experimental species (human, mouse, etc.) .

• Buffer and preservative compatibility: Standard preparations typically use TRIS-buffered saline with 0.02% sodium azide as a preservative .

How can OAS1 antibodies be used to study OAS1 gain-of-function variants in autoinflammatory disorders?

OAS1 gain-of-function variants have been identified in patients with polymorphic autoinflammatory immunodeficiency characterized by recurrent fever, dermatitis, inflammatory bowel disease, pulmonary alveolar proteinosis, and hypogammaglobulinemia . To study these variants:

• Comparative expression analysis: Use OAS1 antibodies to compare protein expression levels between normal and patient-derived samples through Western blotting or immunohistochemistry.

• Functional studies in cell models: Apply OAS1 antibodies in interferon-stimulated cellular systems to observe:

  • dsRNA-independent activity of variant proteins

  • RNase L-mediated RNA-cleavage

  • Translational arrest effects

  • Apoptosis patterns in monocytes, macrophages, and B-cells

• Mechanistic investigations: OAS1 antibodies can help assess how gain-of-function variants impact:

  • B-cell proliferation, differentiation, and co-stimulation

  • Monocyte translation initiation, co-stimulation, and antigen presentation

  • Type I IFN signatures and anti-viral defense mechanisms

• Therapeutic response monitoring: Track changes in OAS1 variant protein expression and downstream effects during experimental treatments (e.g., RNase L-inhibition with curcumin or allogeneic hematopoietic cell transplantation) .

What methodological approaches can be used to investigate OAS1's role in cancer progression?

To investigate OAS1's role in cancer progression using OAS1 antibodies:

• Expression correlation studies:

  • Use OAS1 antibodies to quantify protein levels across cancer stages and correlate with clinical outcomes

  • Compare with mRNA expression data, as high OAS1 mRNA expression has been linked to worse prognosis in breast cancer patients

• Migration and invasion assays:

  • Apply OAS1 antibodies in immunofluorescence studies to track protein localization during cell migration

  • Use neutralizing OAS1 antibodies to block function in migration assays to determine causative relationships

• Signaling pathway analysis:

  • Employ OAS1 antibodies in co-immunoprecipitation experiments to identify cancer-relevant binding partners

  • Perform phospho-specific Western blots to determine activation states in cancer vs. normal cells

• In vivo tumor models:

  • Use OAS1 antibodies for immunohistochemical analysis of tumor sections

  • Correlate OAS1 expression with markers of tumor aggressiveness and metastatic potential

What are recommended protocols for OAS1 antibody validation and optimization?

Multi-step validation process for OAS1 antibodies:

• Initial specificity testing:

  • Western blot using recombinant OAS1 protein alongside cell lysates

  • Include positive controls (interferon-stimulated cells) and negative controls

  • Test for cross-reactivity with other OAS family members

• Application-specific optimization:

  • For immunohistochemistry/immunocytochemistry: Test multiple fixation methods and antigen retrieval techniques

  • For Western blotting: Optimize antibody concentration (typical starting dilution 1:1000)

  • For flow cytometry: Determine optimal permeabilization conditions for this intracellular protein

• Titration experiments:

  • Test serial dilutions of the antibody to determine optimal concentration

  • If staining is weak, increase concentration; if background is high, decrease concentration

  • Document lot-to-lot variation through consistent validation protocols

• Knockout/knockdown validation:

  • Test antibody in OAS1 knockout or siRNA knockdown systems

  • Compare staining patterns in wild-type vs. depleted samples to confirm specificity

How can proteomics approaches enhance OAS1 antibody-based research?

Mass spectrometry (MS)-based proteomics can complement and enhance OAS1 antibody research through:

• Database expansion for antibody validation:

  • Traditional protein databases like UniProt contain limited antibody sequences (only 1095 entries as of 2024)

  • The Observed Antibody Space (OAS) database offers millions of potential human antibody sequences, enabling more comprehensive analysis

• Confirmation of OAS1 antibody specificity:

  • MS can identify off-target binding proteins in immunoprecipitation experiments

  • Bottom-up proteomics approaches allow validation of antibody-enriched fractions

• Detection of post-translational modifications:

  • MS can reveal modifications on OAS1 not detectable by standard antibody methods

  • Combine antibody enrichment with MS analysis for comprehensive PTM mapping

• Quantitative comparison across sample types:

  • Blood plasma vs. depleted plasma comparison reveals antibody enrichment patterns

  • Negative controls (e.g., brain cortex samples) confirm specificity of detection

Proportions of antibody peptides detected across sample types:

This data confirms the validity of newly detected peptides as genuine antibody components .

How should researchers address non-specific binding issues with OAS1 antibodies?

When encountering non-specific binding with OAS1 antibodies:

• Optimize blocking conditions:

  • Test different blocking agents (BSA, normal serum, commercial blockers)

  • Extend blocking time to reduce background

  • Consider adding 0.1-0.3% Triton X-100 to blocking buffer to reduce hydrophobic interactions

• Antibody dilution optimization:

  • Perform serial dilutions to identify optimal concentration

  • If background is high, decrease antibody concentration

  • If specific signal is weak, increase concentration

• Pre-absorption controls:

  • Incubate antibody with recombinant OAS1 protein prior to application

  • Compare pre-absorbed antibody with standard antibody to identify non-specific signals

• Cross-reactivity testing:

  • Test antibody on samples known to lack OAS1 expression

  • Verify specificity against other OAS family members

  • Confirm results with a second OAS1 antibody targeting a different epitope

• Buffer optimization:

  • Adjust salt concentration to reduce ionic interactions

  • Add mild detergents to reduce hydrophobic binding

  • Consider presence of preservatives that may affect binding (e.g., 0.02% Sodium Azide)

What controls are essential when using OAS1 antibodies in experimental settings?

Essential controls for OAS1 antibody experiments:

• Positive controls:

  • Interferon-stimulated cells with confirmed OAS1 upregulation

  • Recombinant OAS1 protein for Western blot ladder verification

  • Tissues known to express OAS1 (e.g., immune cells after viral stimulation)

• Negative controls:

  • Secondary antibody-only controls to assess background

  • Isotype controls (e.g., normal polyclonal IgG from the same species)

  • Non-expressing tissues (e.g., brain cortex samples show ~0.8% detection rate)

  • OAS1 knockout or knockdown samples when available

• Specificity controls:

  • Competitive binding with excess recombinant OAS1

  • Comparison with alternative OAS1 antibody clones

  • Verification across multiple detection methods (Western blot, IHC, flow cytometry)

• Technical controls:

  • Loading controls for Western blots (housekeeping proteins)

  • Tissue processing controls for IHC (known antibodies with consistent performance)

  • Fluorophore controls for confocal microscopy (spectral overlap assessment)

How are OAS1 antibodies contributing to viral immunity research, particularly in SARS-CoV-2 studies?

OAS1 antibodies are advancing viral immunity research, particularly for SARS-CoV-2, through:

• Antiviral mechanism elucidation:

  • Tracking OAS1 expression patterns during infection progression

  • Characterizing OAS1's interaction with viral dsRNA components

  • Investigating the RNase L activation pathway during SARS-CoV-2 infection

• Proteomics integration:

  • The Observed Antibody Space (OAS) database contains 30 million heavy antibody sequences from 146 SARS-CoV-2 patients, enabling expansion of proteomics databases

  • Database searches using this expanded repertoire allow detection of previously unidentified antibody peptides in SARS-CoV-2 plasma samples

  • The newly discovered antibody peptides show diagnostic potential, distinguishing diseased from healthy samples

• Host response characterization:

  • Monitoring OAS1 expression in different patient populations

  • Correlating OAS1 levels with disease severity and outcomes

  • Investigating potential genetic variants affecting OAS1 function during infection

• Therapeutic development implications:

  • Using OAS1 antibodies to screen compounds that modulate its activity

  • Identifying patients who might benefit from RNase L pathway modulation

  • Studying OAS1-targeting therapeutic antibodies for antiviral applications

What novel approaches are being developed for engineering antibodies with specific binding profiles for OAS1 research?

Recent advances in antibody engineering relevant to OAS1 research include:

• Phage display selection techniques:

  • Multiple rounds of selection with appropriate pre-selection steps to remove non-specific binders

  • Systematic collection of phages at each step to monitor antibody library composition

  • Selection against defined ligand complexes to enhance specificity

• Computational modeling for specificity design:

  • Biophysics-informed modeling combined with selection experiments

  • Energy function optimization to design antibodies with predefined binding profiles:

    • Cross-specific binding: jointly minimizing energy functions for desired ligands

    • Specific binding: minimizing energy for desired ligand while maximizing for undesired ligands

• Validation through comparative testing:

  • Experimental testing of computationally designed variants not present in training sets

  • Assessment of model's capacity to propose novel antibody sequences with customized specificity profiles

• Application to OAS1 research:

  • Development of antibodies that specifically distinguish between OAS1 isoforms

  • Creation of antibodies that recognize activated vs. inactive OAS1 conformations

  • Engineering antibodies that selectively bind gain-of-function variants for diagnostic applications