# 12) Host Response

**R-2A activity** of project UN2 — Understand (Applied Research)  
**Program element:** 0602384BP — Chemical and Biological Defense Program  
**Component:** Defense-Wide · **Budget Activity:** 2  
**Vintage:** President's Budget PB2027  
**Canonical URL:** https://hitchintel.com/programs/0602384BP/UN2/a11  
**Parent:** https://hitchintel.com/programs/0602384BP/UN2

## Summary

This activity requests $18.2M in FY2027, 19% of project UN2, up 42% on FY2026. The R-2A exhibit describes it across FY2025–FY2027, including what the FY2027 money is planned to buy.

## What the FY2027 request buys

**FY2027 planned work.** - Maintain and expand core host response characterization capabilities, predictive/in silico tools, and technologies for CB agent characterization, both computer-based as well as in living tissues – emphasizing the use of organ-on-a-chip technologies when possible. - Continue empirical studies addressing host response gaps for traditional and advanced CB agents identified by gap analyses. Maintain and expand characterization capabilities and expertise by tackling traditional gaps increasing capacity and pre-positioning expertise to any emerging CB threat. -Continue refinement of human effects estimates for additional CB agents providing high fidelity data to protect the warfighter against CB threat exposure. -Maintain and expand upgrades for computer-based prediction of physical and toxicological properties for chemical compounds and continue to assess the host responses to mixed agents and novel/emerging threats.

**FY2026 to FY2027 change.** Program/project funding transferred from another funding line. Funding transferred from Project EN2/Enabling Investments Enabling Science thrust area to Project UN2/Understand Host Response thrust area to expand host response characterization of biological agents of concern.

## Before the request year

**FY2026 plans — current year.** - Continue studies to address host response areas for traditional CB agents that earlier gap analyses have identified with methodologies that are also directly applicable to any emerging CB threat. - Continue to implement improvements and upgrades for artificial intelligence/machine learning (AI/ML) based prediction of physical and toxicological properties as one key new tool and continue to assess the body’s response to mixed agents and any novel/emerging threats. - Incorporate AI/ML predictions to refine in vitro and in vivo toxicological assessment to select experimentation most likely to yield actionable results.

**FY2025 accomplishments.** - Augmented predictive methods and technologies for CB agent characterizations, both computer-based as well as in living tissues – emphasized the use of organ-on-a-chip technologies to replace older methodologies. - Continued empirical studies addressing host response gaps for traditional and advanced CB agents identified by gap analyses. Augmented characterization capabilities and expertise by tackling traditional gaps increasing capacity and pre-positioning expertise to tackle any emerging CB threat. - Finalized refinement of human health estimates for key CB agents providing high fidelity data to protect the warfighter against CB threat exposure. - Implemented improvements and upgrades for computer-based prediction of physical and toxicological properties for chemical compounds and continued to assess the host responses to mixed agents and novel/emerging threats.

## Funding

| Fiscal Year | Estimate Type | Amount ($M) |
|---|---|---|
| FY2025 | Actual | 10.0 |
| FY2026 | Enacted | 12.8 |
| FY2027 | Request | 18.2 |

> Prior, current and budget year only — an R-2A activity carries no five-year plan. It sums exactly into its project in the request year and not necessarily in any other.

## Other activities in project UN2

- 11) First Look — FY2027 9.9
- 3) Chemical Biological Radiological Nuclear Situational Awareness — FY2027 8.6
- 15) Unconventional Detection Modalities - Biological Detection — FY2027 7.4
- 9) Employment Characterization — FY2027 6.3
- 10) Environmental Response — FY2027 6.1
- 21) Technical Surprise - Threat Agent Science Data and Optimization (TASDO) — FY2027 6.0
- 13) Operational Biological Sensing — FY2027 4.7
- 19) Technical Surprise — FY2027 4.5
- 5) Diagnostic Building Blocks — FY2027 4.0
- 20) Technical Surprise - Enhanced Biological Defense — FY2027 3.0
- 6) Emerging Threats — FY2027 2.4
- 18) Unconventional Detection Modalities - Chemical Detection — FY2027 2.0
- 14) Emerging and Enhanced Biothreat Sensing — FY2027 2.0
- 16) Operational Chemical Sensing - Chemical Detection — FY2027 1.9
- 2) Chemical Biological Radiological Nuclear Decision Aids — FY2027 1.8
- 17) Modernized and Enhanced Chemical Sensing - Chemical Detection — FY2027 1.8
- 4) Operational Diagnostics — FY2027 1.6
- 1) Chemical Biological Radiological Nuclear Battlespace Sensing, Alerting, and Response — FY2027 1.4
- 7) Diagnostic Building Blocks - Enhanced Biological Defense — FY2027 —
- 8) Emerging Threats - Enhanced Biological Defense — FY2027 —

## Source & machine access

- **Source:** FY2027 Office of the Secretary of Defense RDT&E Budget Justification, Exhibit R-2A, PE 0602384BP project UN2 (PB PB2027). Narrative is the government's own text.
- **No marks, no contractors at this grain** — congressional marks land on the program element and R-3 performers on the project.
- **MCP:** `mcp.hitchintel.com` — `budget_get_activity`.

*HitchAI is an independent intelligence service, not affiliated with the U.S. Department of Defense. Budget figures are requests/estimates, not obligations.*