Domain: Healthcare — Basic Immunology
Target concept: Dendritic Cell Detection (Fluorescent Antibody Method)

Video generation prompt: Fluorescent antibody detection of dendritic cells. Demonstration of cell smears prepared on glass slides, fixation, blocking, addition of fluorescently labeled anti-dendritic cell antibodies, washing, mounting, and observation under a fluorescence microscope. Only key instruments and continuous procedural steps are clearly shown.

Evaluation guide:
(i) Target concept: Specific immunofluorescent detection of dendritic cells via surface marker binding.
Minimum mechanism: Antibody must be fluorescently labeled, must bind only to dendritic cell–specific epitopes, and binding must produce localized, morphologically distinctive fluorescence visible only after proper washing and mounting: no signal without antibody, no signal on non-DC cells, and signal must reflect true dendritic architecture.
(ii)Storyline: Frame 1–2: Glass slide with wet cell smear (visible edge meniscus). Frame 3: Acetone droplet applied and spreads uniformly. Frame 4: Serum blocker dispensed. Frame 5: Fluorescent antibody (green/red) dispensed onto same area. Frame 6: Wash buffer flows across slide. Frame 7: Mounting medium drop placed and coverslip lowered. Frame 8–10: Microscope eyepiece view transitions to fluorescence mode, revealing bright, branched, stellate fluorescent cells, all within fixed center-frame viewpoint, no cuts or repositioning.

Manual:
Experimental Procedure
1. Prepare cell smear on clean glass slide.
2. Fix with cold acetone for 10 min.
3. Block with serum to prevent non-specific binding.
4. Add fluorescently labeled anti-dendritic cell antibody.
5. Wash, mount with antifade medium, observe under fluorescence microscope.
Observation of Experimental Phenomena
Bright, branched, dendritic-shaped fluorescent signal localized to cell bodies and processes against dark background; no fluorescence in control (no antibody) areas.
Summary of Experimental Principles
Dendritic cells express specific surface markers (e.g., CD11c, CD209); fluorescent antibodies bind selectively, enabling visualization via fluorescence microscopy.

Prompt Grounding rubric:
level_1: No glass slide is shown, no fluorescently labeled antibody reagent appears, no fluorescence-microscope view appears, and no cell-smear preparation or mounting step is visible; the core objects and actions from the prompt are missing entirely.
level_2: At least one core item appears (a glass slide, or a labeled antibody reagent, or a microscope), but the procedure is out of order or incomplete, for example mounting is shown before the antibody step, or fixation is skipped altogether.
level_3: All five procedural steps appear in the correct order (smear on slide, fixation, blocking, addition of the fluorescently labeled anti-dendritic-cell antibody, and washing/mounting/fluorescence observation), but at least one step is missing its expected object, e.g., the antibody step shows no visible bottle or pipette, or an unlabeled/non-fluorescent reagent is used instead.
level_4: Everything at the 3-point level holds, plus: each step shows its expected object (smear visible on the slide, a fixative applied, a blocking solution dispensed, the fluorescently labeled anti-dendritic-cell antibody visibly added, a wash step, mounting medium and coverslip applied), and the final frame is a microscope eyepiece view; but one non-core detail is off, such as that final view being poorly framed or showing mostly empty field rather than the smear area.
level_5: Everything at the 4-point level holds, plus: every step has the correct object with the correct visual identity (a labeled antibody container with a visible fluorophore color cue, a glass slide with a distinct smear, a coverslip mounted flush against the slide, and a final microscope eyepiece view centered on the smear area); no object is missing, swapped, or out of order; the same slide and antibody are used continuously from smear through observation.

Scientific and Causal Correctness rubric:
level_1: Fluorescent signal shows up in the wrong context, for example it's visible before the antibody is ever added, it appears on the slide surface or coverslip rather than on cells, or the glowing shapes look nothing like cells (a uniform glow, dust specks, or fiber-like debris); there's no visible link between adding the antibody and the signal appearing.
level_2: Fluorescence only appears after the antibody step, but it looks biologically wrong for this stain, for example the whole cell glows uniformly with no branching arms, or the fluorescence sits only in a round, nucleus-shaped blob rather than spreading toward the cell edges; the labeled cells look flat and rounded rather than star-shaped.
level_3: Fluorescence appears only after the antibody and wash steps; the final microscope view shows distinct bright spots or a few short branch-like extensions on a dark background (some non-uniform cellular signal is present), but the cells don't clearly show the long, tapering, radiating arms typical of dendritic cells, and the glowing cells don't clearly stand out from an otherwise dark, signal-free background.
level_4: Everything at the 3-point level is present, and additionally: the final microscope view shows bright cells with several thin arms radiating outward from a central body, giving a star-like (stellate) shape against a dark background, with little to no glow elsewhere on the slide; but the glow looks smeared evenly across the whole cell rather than concentrated at the body and its arms.
level_5: Everything at the 4-point level is present, and additionally: fluorescence appears only after the antibody and wash steps, never before; the final view shows bright cells with a clear central body and at least three thin, tapering arms radiating outward, each at least twice as long as the cell body, giving an unmistakable star/branched shape rather than a round or flat outline; the background between cells stays dark with no stray glow; the sequence from antibody addition to glowing cells to this branched shape is visually obvious from the video alone.

Spatiotemporal Consistency rubric:
level_1: The glass slide's position on screen jumps between two different spots with no camera pan connecting them, as if two separate clips were spliced together; the microscope eyepiece view cuts straight to a different framing with no transition; the antibody bottle or pipette is on the slide in one moment and simply not there in the next frame while liquid is still mid-pour; the wet smear on the slide turns fully dry in a single instant with no evaporation or wiping motion shown.
level_2: The slide's orientation flips by roughly 90 degrees between the fixation and antibody steps; the pipette moves toward the slide with no visible hand guiding it; fluorescence appears in the final frame with no antibody-addition step shown beforehand; the view switches from bright-field to fluorescence instantly, with no dimming or filter-change cue.
level_3: The slide stays centered and reagents are always added from the same general direction; the microscope stays in the same fixed position; the pipette's motion toward and away from the slide is continuous rather than jumpy, but there is one small hiccup, such as a brief black flash between the washing and mounting steps, or the slide edge briefly leaving the frame during mounting.
level_4: Everything at the 3-point level holds, plus: the slide, pipette, and coverslip keep a consistent scale and viewing angle throughout, with no rotation, flip, or object popping in or out; the switch from bright-field to fluorescence view is shown as a gradual dimming with a visible filter change rather than an instant cut, but one small physical implausibility remains, such as the mounting-medium droplet spreading unrealistically fast across the slide.
level_5: Everything at the 4-point level holds, plus: the slide stays fully visible and in the same position for the whole sequence; the pipette and coverslip move with natural, gradually changing speed rather than jumping between positions; the mounting-medium droplet spreads across the slide at a believable pace; the transition from bright-field to fluorescence view is a smooth dimming paired with a visible filter swap, with no sudden jump, tearing, or lighting mismatch anywhere in the clip.